CHAPTER‐14ENVIRONMENTAL CHEMISTRYI) One mark questions and answers1 Name one insecticideA DDT2 Which acid is not present in acid rainHNO3 H2SO4 CH3COOH H2CO3A CH3COOH3 Define the term pollutionA It is a substance present in the environment in greatproportion than its natural abundance and resulting inharmful damage effect4 Name two gases which are responsible for green house effectA CO2 and CH4 gases5 Which part of the atmosphere contains ozonelayersA Stratosphere contains ozone layers6 What is full form BOD and DDTA BOD Biochemical oxygen Demand and DDT Dichchloro‐ ‐Diphenyl Trichloro ethane7 What are PCBsA Poly chlorinated biphenyls (PCBs) are used as cleansingsolvent detergents and fertilizers cause water pollutionand it is carcinogenic compound8 What is PANA Peroxyacetyl nitrate (PAN) is one of the components ofphoto chemical smog and it is powerful eye irritant

9 What is desirable concentration of F‐ ions and PH of drinking waterA Desirable concentration of F‐ ions is 1ppm or 1mgdm 3‐and PH is 55 to 9510 Name the oxides of nitrogenA Nitric oxide (NO) and Nitrogen dioxide (NO2)11 Which gas caused Bhopal gas tragedy Give its formulaA Methyl isocyanate (MIC) and its molecular formulaCH3N=C =012 Write any two common chemicals of photochemical smogA Acrolein and formaldehyde13 Which can damage the great historical monumentTajmahalA Acid rain(CaCO3 (marble) +H2SO4 - CaSO4+H2O+CO2)14 What is effect of excess of SO42‐ion in drinking waterA Excess of SO42 ‐ ion in drinking water causes laxative effect(gt500ppm)15 What is the cause of methemeglobinemiaA Excess of nitrate ion (gt50ppm) in drinking water causemethemeglobinemia (blue baby syndrome)16 What is troposphereA The lower regions of atmosphere in which the human beingsalong with other organisms live are called troposphere It

extends up to the high of ~10KM from sea level

17 What is stratosphereA Above the troposphere between 10 and 50km above sealevel lies is called stratosphere

18 Name the harmful radiation emitted from sunA UV radiation

19 Which type of harmful radiations absorbed in ozone layersA UV radiation

20 Name the types of pollutants cause troposphere pollutionA 1 Gaseous air pollutants2 Particulate pollutants

21 What are the sources of dissolved oxygen inwaterA In water the source of oxygen is either atmosphericoxygen or photosynthesis carried in plants during day light

22 Which of the following gases is not a green house gas

CO CO3 CH4 H2O vapoursA CO is not a green house gas

23 What type of radiation are absorbed by CO2 in theatmosphereA IR radiations24 Name the oxide of carbonA CO amp CO2

25 What is green house effectA The increase in temperature of atmosphere due topresence of gases like CH4 CO2 and water vapours whichabsorb infrared radiation is called green house effect

II) Two marks questions and answers

1 Name two herbicidesA NaClO3 (sodium chlorate) andNa3AsO3 (Sodium Arsenite)

2 List any two harmful effects of smogA 1 Ozone PAN Act as powerful eye irritants2 Ozone and nitric irritate the nose and throat and theirhigh concentration causes headache chest pain and dryness ofthe throat cough and difficulty in breathing

3 Write any two achievement of green chemistryA 1Development of polystyrene foam sheet packaging

material this Technology allows eliminations CFCS whichcontribute to ozone depletion global warming and groundlevel smog2 Catalytic hydrogenation of diethanolamine in whichenvironmental friendly herbicide is produced in less dangerousways

4 Define environmental chemistryA It is the study of chemical and biochemical process occurringin nature(OR)It deals with the study of origin transport relation effects andfates of various chemical species in the environment5 What do you mean by ozone hole What are itsConsequencesA Ozone hole implies distribution of the ozone layer by theHarmful UV radiations the depletion will virtually resultIn creating some sort of holes in the blanket of ozone whichsurround us As a result the harmful radiations cause skincancer loss of sight and also affect our immune system6 What do you mean by Biochemical oxygen demandA Biochemical oxygen demand is the amount of oxygenrequired by bacteria to decompose organic matter in a certainvolume of sample of water Clean water would have BOD valueof less than 5ppm where as highly polluted water has a BOD of17ppm or more

7 How does detergent cause water pollutionA Tetrachlorothene (Cl2C=CCl2) was used as solvents for drycleaning of clothes This compound is suspected to carcinogenicand contaminated the suspected to carcinogens for bleachingcloths in the laundry hydrogen peroxide (H2O2)is being usedwhich gives better result and is not harmful detergents producepathogens which are diseases causing bacteria and result ingastrointestinal diseases8 Write the methods for management of waste material1 Recycling materials are recycled which saves the cast of raw‐material and waste disposal2 Sewage treatment3 Burning and Incineration4 Digesting5 Dumping9 Write the chemical reaction take place during acid rain in the atmosphereA 1 H2O + CO2 ‐‐‐‐‐‐‐gt H2CO3

2 H2CO3 ‐‐‐‐‐‐gt H++ HCO3‐3 2SO2 + O2 + 2H2O ‐‐‐‐‐‐gt 2H2SO4

10 For your agriculture field or garden you have developed acompost producing pit Discuss the process in the light of badodour files and recycling as wastes for a good produceA It is essential to take proper care of the compost producingpit in order to protect ourselves from bad odour and files It

should be kept covered to minimize bad odour and preventfiles from entering itThe recyclable waste should not be dumped in the compostproducing pit It should be sent to the industries throughvendors for recycling

11 A large number of fish are suddenly found floating dead ona lake There is no evidence of toxic dumping by you find anabundance of phytoplankton suggest a reason for the fish killA The amount of dissolved oxygen present in water is limitedThe abundance of phytoplankton causes depletion of thisdissolved oxygen This is because phytoplanktons are degradedby bacteria present in water For their decomposition theyrequire a large amount of oxygen hence they consume theoxygen dissolved in water As a result the BOD level of waterdrops below 6ppm inhibiting the growth of fish and causingexcessive fish kill

12 What are harmful effects as depletion of ozone layerA 1) The ozone layer protects the earth from the harmful UVradiation of the sun with the depletion of the layer moreradiation will enter the earthrsquos atmosphere UV radiations are

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

9 What is desirable concentration of F‐ ions and PH of drinking waterA Desirable concentration of F‐ ions is 1ppm or 1mgdm 3‐and PH is 55 to 9510 Name the oxides of nitrogenA Nitric oxide (NO) and Nitrogen dioxide (NO2)11 Which gas caused Bhopal gas tragedy Give its formulaA Methyl isocyanate (MIC) and its molecular formulaCH3N=C =012 Write any two common chemicals of photochemical smogA Acrolein and formaldehyde13 Which can damage the great historical monumentTajmahalA Acid rain(CaCO3 (marble) +H2SO4 - CaSO4+H2O+CO2)14 What is effect of excess of SO42‐ion in drinking waterA Excess of SO42 ‐ ion in drinking water causes laxative effect(gt500ppm)15 What is the cause of methemeglobinemiaA Excess of nitrate ion (gt50ppm) in drinking water causemethemeglobinemia (blue baby syndrome)16 What is troposphereA The lower regions of atmosphere in which the human beingsalong with other organisms live are called troposphere It

extends up to the high of ~10KM from sea level

17 What is stratosphereA Above the troposphere between 10 and 50km above sealevel lies is called stratosphere

18 Name the harmful radiation emitted from sunA UV radiation

19 Which type of harmful radiations absorbed in ozone layersA UV radiation

20 Name the types of pollutants cause troposphere pollutionA 1 Gaseous air pollutants2 Particulate pollutants

21 What are the sources of dissolved oxygen inwaterA In water the source of oxygen is either atmosphericoxygen or photosynthesis carried in plants during day light

22 Which of the following gases is not a green house gas

CO CO3 CH4 H2O vapoursA CO is not a green house gas

23 What type of radiation are absorbed by CO2 in theatmosphereA IR radiations24 Name the oxide of carbonA CO amp CO2

25 What is green house effectA The increase in temperature of atmosphere due topresence of gases like CH4 CO2 and water vapours whichabsorb infrared radiation is called green house effect

II) Two marks questions and answers

1 Name two herbicidesA NaClO3 (sodium chlorate) andNa3AsO3 (Sodium Arsenite)

2 List any two harmful effects of smogA 1 Ozone PAN Act as powerful eye irritants2 Ozone and nitric irritate the nose and throat and theirhigh concentration causes headache chest pain and dryness ofthe throat cough and difficulty in breathing

3 Write any two achievement of green chemistryA 1Development of polystyrene foam sheet packaging

material this Technology allows eliminations CFCS whichcontribute to ozone depletion global warming and groundlevel smog2 Catalytic hydrogenation of diethanolamine in whichenvironmental friendly herbicide is produced in less dangerousways

4 Define environmental chemistryA It is the study of chemical and biochemical process occurringin nature(OR)It deals with the study of origin transport relation effects andfates of various chemical species in the environment5 What do you mean by ozone hole What are itsConsequencesA Ozone hole implies distribution of the ozone layer by theHarmful UV radiations the depletion will virtually resultIn creating some sort of holes in the blanket of ozone whichsurround us As a result the harmful radiations cause skincancer loss of sight and also affect our immune system6 What do you mean by Biochemical oxygen demandA Biochemical oxygen demand is the amount of oxygenrequired by bacteria to decompose organic matter in a certainvolume of sample of water Clean water would have BOD valueof less than 5ppm where as highly polluted water has a BOD of17ppm or more

7 How does detergent cause water pollutionA Tetrachlorothene (Cl2C=CCl2) was used as solvents for drycleaning of clothes This compound is suspected to carcinogenicand contaminated the suspected to carcinogens for bleachingcloths in the laundry hydrogen peroxide (H2O2)is being usedwhich gives better result and is not harmful detergents producepathogens which are diseases causing bacteria and result ingastrointestinal diseases8 Write the methods for management of waste material1 Recycling materials are recycled which saves the cast of raw‐material and waste disposal2 Sewage treatment3 Burning and Incineration4 Digesting5 Dumping9 Write the chemical reaction take place during acid rain in the atmosphereA 1 H2O + CO2 ‐‐‐‐‐‐‐gt H2CO3

2 H2CO3 ‐‐‐‐‐‐gt H++ HCO3‐3 2SO2 + O2 + 2H2O ‐‐‐‐‐‐gt 2H2SO4

10 For your agriculture field or garden you have developed acompost producing pit Discuss the process in the light of badodour files and recycling as wastes for a good produceA It is essential to take proper care of the compost producingpit in order to protect ourselves from bad odour and files It

should be kept covered to minimize bad odour and preventfiles from entering itThe recyclable waste should not be dumped in the compostproducing pit It should be sent to the industries throughvendors for recycling

11 A large number of fish are suddenly found floating dead ona lake There is no evidence of toxic dumping by you find anabundance of phytoplankton suggest a reason for the fish killA The amount of dissolved oxygen present in water is limitedThe abundance of phytoplankton causes depletion of thisdissolved oxygen This is because phytoplanktons are degradedby bacteria present in water For their decomposition theyrequire a large amount of oxygen hence they consume theoxygen dissolved in water As a result the BOD level of waterdrops below 6ppm inhibiting the growth of fish and causingexcessive fish kill

12 What are harmful effects as depletion of ozone layerA 1) The ozone layer protects the earth from the harmful UVradiation of the sun with the depletion of the layer moreradiation will enter the earthrsquos atmosphere UV radiations are

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

extends up to the high of ~10KM from sea level

17 What is stratosphereA Above the troposphere between 10 and 50km above sealevel lies is called stratosphere

18 Name the harmful radiation emitted from sunA UV radiation

19 Which type of harmful radiations absorbed in ozone layersA UV radiation

20 Name the types of pollutants cause troposphere pollutionA 1 Gaseous air pollutants2 Particulate pollutants

21 What are the sources of dissolved oxygen inwaterA In water the source of oxygen is either atmosphericoxygen or photosynthesis carried in plants during day light

22 Which of the following gases is not a green house gas

CO CO3 CH4 H2O vapoursA CO is not a green house gas

23 What type of radiation are absorbed by CO2 in theatmosphereA IR radiations24 Name the oxide of carbonA CO amp CO2

25 What is green house effectA The increase in temperature of atmosphere due topresence of gases like CH4 CO2 and water vapours whichabsorb infrared radiation is called green house effect

II) Two marks questions and answers

1 Name two herbicidesA NaClO3 (sodium chlorate) andNa3AsO3 (Sodium Arsenite)

2 List any two harmful effects of smogA 1 Ozone PAN Act as powerful eye irritants2 Ozone and nitric irritate the nose and throat and theirhigh concentration causes headache chest pain and dryness ofthe throat cough and difficulty in breathing

3 Write any two achievement of green chemistryA 1Development of polystyrene foam sheet packaging

material this Technology allows eliminations CFCS whichcontribute to ozone depletion global warming and groundlevel smog2 Catalytic hydrogenation of diethanolamine in whichenvironmental friendly herbicide is produced in less dangerousways

4 Define environmental chemistryA It is the study of chemical and biochemical process occurringin nature(OR)It deals with the study of origin transport relation effects andfates of various chemical species in the environment5 What do you mean by ozone hole What are itsConsequencesA Ozone hole implies distribution of the ozone layer by theHarmful UV radiations the depletion will virtually resultIn creating some sort of holes in the blanket of ozone whichsurround us As a result the harmful radiations cause skincancer loss of sight and also affect our immune system6 What do you mean by Biochemical oxygen demandA Biochemical oxygen demand is the amount of oxygenrequired by bacteria to decompose organic matter in a certainvolume of sample of water Clean water would have BOD valueof less than 5ppm where as highly polluted water has a BOD of17ppm or more

7 How does detergent cause water pollutionA Tetrachlorothene (Cl2C=CCl2) was used as solvents for drycleaning of clothes This compound is suspected to carcinogenicand contaminated the suspected to carcinogens for bleachingcloths in the laundry hydrogen peroxide (H2O2)is being usedwhich gives better result and is not harmful detergents producepathogens which are diseases causing bacteria and result ingastrointestinal diseases8 Write the methods for management of waste material1 Recycling materials are recycled which saves the cast of raw‐material and waste disposal2 Sewage treatment3 Burning and Incineration4 Digesting5 Dumping9 Write the chemical reaction take place during acid rain in the atmosphereA 1 H2O + CO2 ‐‐‐‐‐‐‐gt H2CO3

2 H2CO3 ‐‐‐‐‐‐gt H++ HCO3‐3 2SO2 + O2 + 2H2O ‐‐‐‐‐‐gt 2H2SO4

10 For your agriculture field or garden you have developed acompost producing pit Discuss the process in the light of badodour files and recycling as wastes for a good produceA It is essential to take proper care of the compost producingpit in order to protect ourselves from bad odour and files It

should be kept covered to minimize bad odour and preventfiles from entering itThe recyclable waste should not be dumped in the compostproducing pit It should be sent to the industries throughvendors for recycling

11 A large number of fish are suddenly found floating dead ona lake There is no evidence of toxic dumping by you find anabundance of phytoplankton suggest a reason for the fish killA The amount of dissolved oxygen present in water is limitedThe abundance of phytoplankton causes depletion of thisdissolved oxygen This is because phytoplanktons are degradedby bacteria present in water For their decomposition theyrequire a large amount of oxygen hence they consume theoxygen dissolved in water As a result the BOD level of waterdrops below 6ppm inhibiting the growth of fish and causingexcessive fish kill

12 What are harmful effects as depletion of ozone layerA 1) The ozone layer protects the earth from the harmful UVradiation of the sun with the depletion of the layer moreradiation will enter the earthrsquos atmosphere UV radiations are

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

CO CO3 CH4 H2O vapoursA CO is not a green house gas

23 What type of radiation are absorbed by CO2 in theatmosphereA IR radiations24 Name the oxide of carbonA CO amp CO2

25 What is green house effectA The increase in temperature of atmosphere due topresence of gases like CH4 CO2 and water vapours whichabsorb infrared radiation is called green house effect

II) Two marks questions and answers

1 Name two herbicidesA NaClO3 (sodium chlorate) andNa3AsO3 (Sodium Arsenite)

2 List any two harmful effects of smogA 1 Ozone PAN Act as powerful eye irritants2 Ozone and nitric irritate the nose and throat and theirhigh concentration causes headache chest pain and dryness ofthe throat cough and difficulty in breathing

3 Write any two achievement of green chemistryA 1Development of polystyrene foam sheet packaging

material this Technology allows eliminations CFCS whichcontribute to ozone depletion global warming and groundlevel smog2 Catalytic hydrogenation of diethanolamine in whichenvironmental friendly herbicide is produced in less dangerousways

4 Define environmental chemistryA It is the study of chemical and biochemical process occurringin nature(OR)It deals with the study of origin transport relation effects andfates of various chemical species in the environment5 What do you mean by ozone hole What are itsConsequencesA Ozone hole implies distribution of the ozone layer by theHarmful UV radiations the depletion will virtually resultIn creating some sort of holes in the blanket of ozone whichsurround us As a result the harmful radiations cause skincancer loss of sight and also affect our immune system6 What do you mean by Biochemical oxygen demandA Biochemical oxygen demand is the amount of oxygenrequired by bacteria to decompose organic matter in a certainvolume of sample of water Clean water would have BOD valueof less than 5ppm where as highly polluted water has a BOD of17ppm or more

7 How does detergent cause water pollutionA Tetrachlorothene (Cl2C=CCl2) was used as solvents for drycleaning of clothes This compound is suspected to carcinogenicand contaminated the suspected to carcinogens for bleachingcloths in the laundry hydrogen peroxide (H2O2)is being usedwhich gives better result and is not harmful detergents producepathogens which are diseases causing bacteria and result ingastrointestinal diseases8 Write the methods for management of waste material1 Recycling materials are recycled which saves the cast of raw‐material and waste disposal2 Sewage treatment3 Burning and Incineration4 Digesting5 Dumping9 Write the chemical reaction take place during acid rain in the atmosphereA 1 H2O + CO2 ‐‐‐‐‐‐‐gt H2CO3

2 H2CO3 ‐‐‐‐‐‐gt H++ HCO3‐3 2SO2 + O2 + 2H2O ‐‐‐‐‐‐gt 2H2SO4

10 For your agriculture field or garden you have developed acompost producing pit Discuss the process in the light of badodour files and recycling as wastes for a good produceA It is essential to take proper care of the compost producingpit in order to protect ourselves from bad odour and files It

should be kept covered to minimize bad odour and preventfiles from entering itThe recyclable waste should not be dumped in the compostproducing pit It should be sent to the industries throughvendors for recycling

11 A large number of fish are suddenly found floating dead ona lake There is no evidence of toxic dumping by you find anabundance of phytoplankton suggest a reason for the fish killA The amount of dissolved oxygen present in water is limitedThe abundance of phytoplankton causes depletion of thisdissolved oxygen This is because phytoplanktons are degradedby bacteria present in water For their decomposition theyrequire a large amount of oxygen hence they consume theoxygen dissolved in water As a result the BOD level of waterdrops below 6ppm inhibiting the growth of fish and causingexcessive fish kill

12 What are harmful effects as depletion of ozone layerA 1) The ozone layer protects the earth from the harmful UVradiation of the sun with the depletion of the layer moreradiation will enter the earthrsquos atmosphere UV radiations are

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

material this Technology allows eliminations CFCS whichcontribute to ozone depletion global warming and groundlevel smog2 Catalytic hydrogenation of diethanolamine in whichenvironmental friendly herbicide is produced in less dangerousways

4 Define environmental chemistryA It is the study of chemical and biochemical process occurringin nature(OR)It deals with the study of origin transport relation effects andfates of various chemical species in the environment5 What do you mean by ozone hole What are itsConsequencesA Ozone hole implies distribution of the ozone layer by theHarmful UV radiations the depletion will virtually resultIn creating some sort of holes in the blanket of ozone whichsurround us As a result the harmful radiations cause skincancer loss of sight and also affect our immune system6 What do you mean by Biochemical oxygen demandA Biochemical oxygen demand is the amount of oxygenrequired by bacteria to decompose organic matter in a certainvolume of sample of water Clean water would have BOD valueof less than 5ppm where as highly polluted water has a BOD of17ppm or more

7 How does detergent cause water pollutionA Tetrachlorothene (Cl2C=CCl2) was used as solvents for drycleaning of clothes This compound is suspected to carcinogenicand contaminated the suspected to carcinogens for bleachingcloths in the laundry hydrogen peroxide (H2O2)is being usedwhich gives better result and is not harmful detergents producepathogens which are diseases causing bacteria and result ingastrointestinal diseases8 Write the methods for management of waste material1 Recycling materials are recycled which saves the cast of raw‐material and waste disposal2 Sewage treatment3 Burning and Incineration4 Digesting5 Dumping9 Write the chemical reaction take place during acid rain in the atmosphereA 1 H2O + CO2 ‐‐‐‐‐‐‐gt H2CO3

2 H2CO3 ‐‐‐‐‐‐gt H++ HCO3‐3 2SO2 + O2 + 2H2O ‐‐‐‐‐‐gt 2H2SO4

10 For your agriculture field or garden you have developed acompost producing pit Discuss the process in the light of badodour files and recycling as wastes for a good produceA It is essential to take proper care of the compost producingpit in order to protect ourselves from bad odour and files It

should be kept covered to minimize bad odour and preventfiles from entering itThe recyclable waste should not be dumped in the compostproducing pit It should be sent to the industries throughvendors for recycling

11 A large number of fish are suddenly found floating dead ona lake There is no evidence of toxic dumping by you find anabundance of phytoplankton suggest a reason for the fish killA The amount of dissolved oxygen present in water is limitedThe abundance of phytoplankton causes depletion of thisdissolved oxygen This is because phytoplanktons are degradedby bacteria present in water For their decomposition theyrequire a large amount of oxygen hence they consume theoxygen dissolved in water As a result the BOD level of waterdrops below 6ppm inhibiting the growth of fish and causingexcessive fish kill

12 What are harmful effects as depletion of ozone layerA 1) The ozone layer protects the earth from the harmful UVradiation of the sun with the depletion of the layer moreradiation will enter the earthrsquos atmosphere UV radiations are

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

7 How does detergent cause water pollutionA Tetrachlorothene (Cl2C=CCl2) was used as solvents for drycleaning of clothes This compound is suspected to carcinogenicand contaminated the suspected to carcinogens for bleachingcloths in the laundry hydrogen peroxide (H2O2)is being usedwhich gives better result and is not harmful detergents producepathogens which are diseases causing bacteria and result ingastrointestinal diseases8 Write the methods for management of waste material1 Recycling materials are recycled which saves the cast of raw‐material and waste disposal2 Sewage treatment3 Burning and Incineration4 Digesting5 Dumping9 Write the chemical reaction take place during acid rain in the atmosphereA 1 H2O + CO2 ‐‐‐‐‐‐‐gt H2CO3

2 H2CO3 ‐‐‐‐‐‐gt H++ HCO3‐3 2SO2 + O2 + 2H2O ‐‐‐‐‐‐gt 2H2SO4

10 For your agriculture field or garden you have developed acompost producing pit Discuss the process in the light of badodour files and recycling as wastes for a good produceA It is essential to take proper care of the compost producingpit in order to protect ourselves from bad odour and files It

should be kept covered to minimize bad odour and preventfiles from entering itThe recyclable waste should not be dumped in the compostproducing pit It should be sent to the industries throughvendors for recycling

11 A large number of fish are suddenly found floating dead ona lake There is no evidence of toxic dumping by you find anabundance of phytoplankton suggest a reason for the fish killA The amount of dissolved oxygen present in water is limitedThe abundance of phytoplankton causes depletion of thisdissolved oxygen This is because phytoplanktons are degradedby bacteria present in water For their decomposition theyrequire a large amount of oxygen hence they consume theoxygen dissolved in water As a result the BOD level of waterdrops below 6ppm inhibiting the growth of fish and causingexcessive fish kill

12 What are harmful effects as depletion of ozone layerA 1) The ozone layer protects the earth from the harmful UVradiation of the sun with the depletion of the layer moreradiation will enter the earthrsquos atmosphere UV radiations are

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

should be kept covered to minimize bad odour and preventfiles from entering itThe recyclable waste should not be dumped in the compostproducing pit It should be sent to the industries throughvendors for recycling

11 A large number of fish are suddenly found floating dead ona lake There is no evidence of toxic dumping by you find anabundance of phytoplankton suggest a reason for the fish killA The amount of dissolved oxygen present in water is limitedThe abundance of phytoplankton causes depletion of thisdissolved oxygen This is because phytoplanktons are degradedby bacteria present in water For their decomposition theyrequire a large amount of oxygen hence they consume theoxygen dissolved in water As a result the BOD level of waterdrops below 6ppm inhibiting the growth of fish and causingexcessive fish kill

12 What are harmful effects as depletion of ozone layerA 1) The ozone layer protects the earth from the harmful UVradiation of the sun with the depletion of the layer moreradiation will enter the earthrsquos atmosphere UV radiations are

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

harmful because they lead to the skin cancer and sun burns2) They cause death of many phytoplanktons which lead to adecrease of fish productivity3) Increase in UV radiation decreases the moisture content ofthe soil and damages both plants and fibres13 What are pathogens Mention its harmful effectA Pathogens are water pollutants include bacteria and otherorganism They enter water from animal excreta and domesticsewage14 What are harmful effects of acid rainA 1 It is harmful for crops2 It damages buildings made up of marble14 Write by two harmful effects of oxides of nitrogen1 Damage the leaves of plants and retard the rate ofphotosynthesis2 Nitrogen dioxide is a lung irritant that can lead to an acuterespiratory disease in children15 Write any two harmful effects of oxide of sulphur1 It causes respiratory diseases eg Asthama bronchitis inhuman beings2 It causes irritation to the eyes resulting in tears and redness16 Write the harmful effects of hydrocarbons pollutantsMention its sourcesHarmful effects1 Hydrocarbons are carcinogenic ie they cause cancer

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

2 They harm plants and shedding of leaves flowers amp twingesSources Incomplete combustion of fuel used in automobiles17 What are the harmful effects of CO Mention its sourcesHarmful effects1 It is high poisonous to living beings when inhaled can reacts with H b to form carboxyhb and reduces the oxygen carrying capacity2 It causes headache weak eyesight nervousness andcardiovascular disorderSources 1 incomplete combustion of coal firewood petroletchellip2 by automobile exhaust18 Write the harmful effect of CO2 mention its sourcesA Harmful effectIt causes global warmingSources 1 Respiration2 Burning of fossil fuels for energy3 By volcanic eruptions4 Deforestation5 By decomposition of limestone during the manufacture ofcements19 Giving example differentiate bw viable and non viableparticulate pollutantsA 1viable particulate They are minute living organisms ‐thatare dispersed in atmosphere

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

Ex Bacteria fungi moulds algae etchellip‐It may be noted that human being are allergic to some of thefungi found in air Fungi can also cause plant diseases2 Non viable particulate‐ They are formed by thebreakdown of larger materials or by condensation of minuteparticles and dropletsEx mists smoke fumes and dust20 During ward war II DDT was found to be of great use for which purpose was is used Why has its use beenbanned in India nowA It is used to control of malaria and other insect bornediseasesAfter the war DDT is used in Agriculture to control thedamages caused by insects weeds and various crop diseasesHowever due to adverse effects its use has been bannedIndia and it is nonbiodegradable and carcinogenic21 Acid rain is known to contain some acids Name theseacids and where from they come in rainA The acids commonly present in acid rain are nitric acidsulphuric acid and carbonic acid Nitric acid is formed byoxidation of nitric oxide present in air to NO2 amp NO3 whichdissolve in water also present in airSulphuric acid is formed by the oxidation of SO2 result in airto SO3 followed by dissolution in waterCO2 present in the acid dissolves in water to give carbonicacidIII) Three marks questions and answers1 Explain tropospheric pollution

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

A Troposphere pollution occurs due to the presence ofundesirable gases and the solid particles in the air the majorgaseous and the Particulate pollutants presents in thetroposphere as follows1 Gaseous air pollutants These include mainly oxides ofsulphur (SO2ampSO3) oxide of nitrogen (NOampNO2) and oxides ofcarbon (COampCO2) in addition to hydrogen sulphide (H2S)hydrocarbons and other oxidants2 Particulate pollutions These include dust mist fumessmoke smog etchellip2 What is smog How is classical smog different from photochemical smogA Smog is a mixture of smoke dust partials and small drops of fog

Classical smog photochemical smog1048766 It occurs in cool humid It occurs in warm dry andClimate sunny climate1048766 It is called reducing smog It is called oxidizing smog1048766 It is a mixture of smoke It is a mixture ofFog and sulphurdioxide unsaturated hydrocarbons ands Oxides of nitrogen3 Statues and monuments in India are affected by acid rainhowA The air around the statues and monuments in India containsfairly high levels of the oxides of sulphur and nitrogenThis is due to a large number of industries and power plants inthe near by areasThe problem has been further aggravated due to use of poorquality of coal kerosene and fire wood as fuel for domestic

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

purposesThe states acid rain affects for marble of these statues andmonumentsCaCO3+H2SO4 gt CaSO‐ 4+H2O+CO2

As a result this away and marble is getting discolored andlusterless Government has given the instructions to keep the air TAJ TRAPEZIUM ( area comprising cities of Agra Firozabad Mathura and Bharatpur) pollution free4 Carbon monoxide gas is more dangerous than carbondioxide gas Why ExplainA It is highly poisonous to living beings because of its ability toblock the delivery of oxygen to the organs and tissues It bindsto haemoglobin complex to form carboxyl haemoglobin (COHb)which is about 300 times more stable than oxy hemoglobin‐complex In the blood when the concentration of carbonhaemoglobin reaches about 3 4 percent the oxygen carrying‐capacity blood is greatly reduced This oxygen deficiencyresults in to headache weak eyesight nervousness andcardiovascular disorder CO2 does not combine withhaemoglobin and hence is less harmful as pollutant but it is themain contributor forwards green house effect amp globalwarming5 What are pesticides and herbicides Give examplesA Pesticides These are a mixture of two or more substancesThey are used for killing pests Pests include insects plantspathogens weeds mollusks etchellip that destroys the plant cropand spread diseases

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

ex Aldrin and Dieldrin‐Herbicides These are chemicals specially meant for killingweeds Ex Sodium chlorate (NaClO‐ 3)Sodium Arsenite (Na3 AsO3)6 Define environmental pollution Name its typesA The addition of any undesirable material to air water andsoil by a nature sourceorDue to human activity to such a level of concentration warmadversely affects the quality of environment is calledenvironmental pollutionTypes1 Water pollution2 Soil pollution3 Air pollution8 How can domestic waste be used as manureA Depending upon the nature of the waste domestic waste canbe segregated in to two categories ie biodegradable and nonbiodegradables Biodegradables waste such as leaves rottenfood etchellip should be deposited in land hills where they getdecomposed aerobically and anaerobically in to manure Nonbiodegradable waste (Which cannot be degraded) such asplastic glass metal scrapes etchellip should be sent for recycling9 Write short note on a)BOD b) Photo chemical smog c)Ozone hole

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

A BOD Biochemical oxygen demand is defined as the amountof oxygen required to oxidise the pollutants presents in waterWater having BOD less than 5ppm is clean water and greaterthan 17ppm is polluted waterPhoto chemical smog It consists of oxides of nitrogen which absorb light and form free radicalsIt is extremely harmful and is oxidizing in natureOzone hole ozone layer is depleted near Antarctica and it iscalled ozone hole10 Define green chemistry Explain with one exampleChemistry and chemical process involving the minimum useand generation of harmful substances is called green chemistryEx Earlier tetrachloroethene themes was used as solvents for‐dry cleaning This compound is carcinogenic therefore it hasbeen replaced by liquefied CO2 along with a suitable detergentwhich is less harmful11 What are the reactions involves for ozone layer depletion in the stratosphereA CFCrsquoS (chlorofluorocarbons) that are released in theatmosphere mix with the other atmospheric gases and wheneventually reach the stratosphere gets broken down by UVradiations as fallowsCF2Cl2 ‐‐‐‐‐‐gt Cl+ CF2Cl

The chlorine radical reacts with ozone and breaks down ozonemolecule as followsCl+ O3 ‐‐‐‐‐gt ClO+ O2

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

ClOradical further reacts with atomic oxygen and producesmore chlorine radicals as followsClO+ O ‐‐‐‐‐‐gt Cl+ O2

12 Write the chemical reactions formation of oxides of nitrogen Mention its sourcesANS1 N2(g)+O2(g) ‐‐‐‐‐‐gt2NO(g)

2 2NO(g + O2(g ‐‐‐‐‐‐gt 2NO2(g)

3 NO(g)+O3(g) ‐‐‐‐‐‐gt NO2(g)+O2(g)

Sources 1 At high attitude when lightning strokes dinitrogenand dioxygen combine to form oxides of nitrogen2 Burning of fossil fuels in an automobile engine at hightemperature dinitrogen and dioxygen combine to yieldsignificant quantities of nitric oxide and nitrogen dioxide13 Write the chemical reactions for the formation of oxides ofsulphur Mention its sourcesA 1 2SO2 + O2 ‐‐‐‐‐‐gt 2SO3

2 SO2 +O3 ‐‐‐‐‐‐‐gt SO3 + O2

3 SO2 + H2O2 ‐‐‐‐‐‐gt 2H2SO4

Sources Burning of fossil fuels containing sulphur14 Write down the chemical equation of reactions involved during the formation of photochemical smog How can it be controlledA Photochemical smog is formed by absorption of sunlightby oxides of nitrogen to form free radicals which are highlyreactive

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

a) NO2 ‐‐‐‐‐‐‐gt NO+ O

b) O+ O2 ‐‐‐‐‐‐gt O3

c) N O+ O3 ‐‐‐‐‐‐gtNO 2 + O 2d) 3CH4 + 2O3 ‐‐‐‐‐‐gt3HCHO + 3H2OIt can be prevented by spraying chemicals which will destroyfree radicals in the atmosphereIV) Four marks questions and answers1 Explain the reactions involved during the formation ofphotochemical smogA Photochemical smog is formed as a result of the reactionof sunlight with hydrocarbons and nitrogen oxidesOzone nitricoxide Acrolein formaldehyde andperoxyacetyl nitrate are common compounds asphotochemical smogThe formation of photochemical smog can be burning as fossilfuels leads to the emission of hydrocarbon and nitrogen dioxidein atmosphere High concentration of these pollutants in airresults in their interaction with sunlight as fallows1 NO2(g) gtN O‐

(g)+ O(g)

2 O(g)+O2(g) gtO‐ 3(g)

3 O3(g)+N O(g) gtNO‐ 2(g)+ O

(g)

While ozone is toxic in nature both NO2amp O3 are oxidizingagents They react with the unburnt hydrocarbons in air toproduce formaldehyde PAN and Acrolein4 3CH4+2O3 gt3 HCHO+3H‐ 2OPAN (CH2=CH CH=O) and‐Acrolein (CH3 COOONO2)

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

2 What are harmful effects of photochemical smog and how can they be controlledA 1 Ozone and PAN acts as powerful eye irritants2 Ozone and nitric oxide irritate the nose and throat andthen high concentration cause headache chest pain anddryness of the throat cough and difficulty in breathinga It also cause and corrosion and painted surfacesBIt leads to cracking of rubber and extensive damage toplants lifeControl of photochemical smog1 Use of catalysts converters in automobiles Which preventsthe release of oxides of nitrogen and hydrocarbons to theatmosphere2 Certain plants eghellippines Juniparus quercus pyrus and vitiscan metabolize oxides of nitrogen and therefore theirplantation could help in this matter3 What are the major causes of water pollution ExplainA 1 Pathogens These are water pollutants include bacteriaand other organismsThey enter water from animal excretaand domestic Sewage Bacteria presents in human excretacauses gastrointestinal diseases (Excreta contains escherichiaCoil and streptococcus faecalis)2 Organic wastes These are biodegradable water that polluteswater as a result run off The presence of excess of organicwastes in water decreases the amount of oxygen held by waterThis decrease in the amount of dissolved oxygen inhibitsaquatic life3 Chemical pollutants These are the water soluble chemicals

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

like heavy metals such as cadmium mercury nickel etchellipThe presence of these chemicals (above the tolerancelimit) can damage the kidneys central nervous systemand liver4 What do you mean by green chemistry How will it help in decreasing environmental pollutionA It is a production process that aims at using the existingknowledge and principles of chemistry for developing andimplenting chemical products and processes to reduce the useand generation if substances hazardous to the environmentThe release of different harmful chemicals (particulates gasesorganic and inorganic wastes) causes environmental pollutionIn green chemistry the reactants to be used in chemicalreactions are chosen in such way that the yield of the endproducts is up to 100 This prevents or limits chemicalpollutants from being introduced in to the environmentFor example through the efforts of green chemists H2O2 hasreplaced tetrachloromethene and chlorine gas in drying andbleaching of paperCO2 has replaced CFCs as blowing agents in manufacture ofpolystyrene foam sheet5 Name the pollutants which cause soil pollutionA1 Pesticides2 Insecticides3 Herbicides4 Fungicides5 Industrial wastes

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

6 Urban wastes7 Agriculture pollutants8 Fertilizers6 What is green house effect How does it affect the globalclimateA It is the phenomenon in which earthrsquos atmosphere trap theheat from the sun and prevent it form escaping in to the outerspaceGreen house gases such as CO2 CH4 ozone chlorofluorocarboncompounds and water vapour in the atmosphere result inclimate changes sunlight intense a green house through Thetransparent glass or plastic panes and heats the plants by theheat emitted by the plants in the form of infrared radiationcannot puss through the glass or plastic panes As a result ofinside temperature increases Increased CO2 levels in theatmosphere can also cause plants undergoing photosynthesisto take use the gas at a greater rate so that plants in warmerclimate with adequate rainfall would grow faster An increase inaverage global temperature to increase the incidence ofinfectious diseases like malaria sleeping sickness dengue andyellow fever CFCs are also damaging ozone layer The averageglobal temperature increase to a level which may lead meltingpolar ice caps and flooding of lying areas all over the earthThere may be less rain fall in temperature zones and more rainfall in the drier areas of the world (CO2 in the major contributeto global warming)7 What is acid rain How is it harmful to the environment

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water

A When the PH of the rain water below 56 due to thepresence of oxides of sulphur amp nitrogen and carbon dioxide inthe atmosphere is called acid rainHarmful effects of acid rain1 It is toxic to vegetation and aquatic life2 It damages building and states and dissolves heavy metalsfrom soils rocks and sedimentals Tajmahal has beendamaged by acid rain3 The heavy metal ions such as copper lead and aluminumleached from the soil enter well water and producedvariety of toxic effects4 Acid rain also corrodes water pipes resulting in theleaching as heavy metals such as iron lead and copper into drinking water