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UCSKM PUBLIC SCHOOL

CLASS-XII

CHEMISTRY ASSIGNMENT

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Solid State

1. Distinguish between crystalline & amorphous solids.

OR

Crystalline solids are anisotropic, what does this statement mean.

2. How does amorphous silica differ from Quartz?

3. How the Schottky defect differs from Frenkel defect? Explain with suitable example.

4. CsCl has bcc arrangement and its unit cell edge length is 400pm. Calculate the interionic distance in CsCl.

5. Define F-centres. Mention some properties of solids which have F-centres in the crystals.

6. What do you mean by intrinsic semiconductor? Explain with the help of an example.

7. Define n-type and p-type semiconductors.

8. How does the electrical resistivity of the following classes of material vary with temperature?

(a) Semiconductors (b) Metallic conductors (c) Super conductors

9. Define the following:

(a) Ferromagnetism (b) Antiferromagnetism (c) Ferrimagnetism.

10. The density of potassium bromide crystal is 2.75 gcm-3 and length of an edge of a unit cell is 654 pm. The unit cell of KBr is one of the three cubic cells. Does the unit cell have a NaCl or CsCl structure?

11. Calculate the Avagadro’s number from the following data:

Density of NaCl = 2.165 gcm-3, distance between Na+ and Cl-- in NaCl = 281pm.

12. The compound CuCl has the ZnS (cubic) structure. Its Density is 3.4 gcm-3. What is the length of the unit cell?

13. In corundum, oxide ions are arranged in h.c.p. array and the aluminium ions occupy two thirds of octahedral voids. What is the formula of corundum?

15. An element of atomic mass 98.5 gmol-1 occur in fcc structure. If its unit cell edge length is 500 pm and its density is 5.22 gcm-3. What is the value of Avogadro constant?

16. Account the following:

(a) Silicon is an insulator but silicon doped with phosphorus acts as a semiconductor.

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(b) Some of the glass objects recovered from ancient monuments look milky instead of being transparent.

17. How the crystalline solids are classified on the basis of the nature of bonding? Give suitable examples and nature of the forces present in different types of solids.

18. Give the reasons for the following:

(a) Molecular solids are generally soft and easily compressible.

(b) The energy required to vapourise one mole of copper is smaller than that of energy required to vapourise one mole of diamond.

(c)All metals have metallic bonds but some metals are soft and having low melting points and some are hard and having high melting points.

(d)Covalent crystals like diamond and silicon carbide are quite hard and difficult to break.

(e) Ionic solids, inspite of being made up of ions, do not conduct electricity.

19. Draw a diagram of a unit cell of sodium chloride. In which of three structural forms simple cubic, face centred and body centred cubic are the ions of sodium chloride separately arranged. What is the coordination around sodium ions?

OR

Draw a neat diagram for sodium chloride structure and then describe it accordingly.

20. How will you distinguish between the following terms:

(a) Hexagonal close packing and cubic close packing

(b) Crystal lattice and unit cell

(c) Tetrahedral void and octahedral void

21. Calculate the efficiency of packing in case of a metal crystal for (with the assumption that atoms are touching each other)

(a)Simple cubic (b) Body centered cubic (c) Face centered cubic

22. A cubic solid is made of two elements P and Q. Atoms Q are at the corners of cube and P at the body centre. What is the formula of the compound? What are the coordination number of P and Q?

23. In a crystalline solid, anions Y-- are arranged in ccp arrangement. Cations X+ are equally distributed between octahedral and tetrahedral voids. If all the octahedral voids are occupied, write the formula of the solid.

24. Analysis shows that nickel oxide has formula Ni0.98 O1.0. What fraction of the nickel exists as Ni2+ and Ni3+ ions?

25. Why is glass considered a super cooled liquid?

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26. Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show cleavage property?

27. Classify the following solids in different categories based on the nature of intermolecular forces operating in them: Potassium sulphate, tin, benzene, urea, ammonia, water, zinc sulphide, graphite, rubidium, argon, silicon carbide.

28. Solid A is a very hard electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?

29. Ionic solids conduct electricity in molten state but not in solid state. Explain.

30. Classify each of the following solids as ionic, metallic, molecular, network (covalent) or amorphous.

(a) Tetraphosphorousdecoxide (P4O10)

(b) Graphite

(c) Brass

(d) Ammonium Phosphate [(NH4)3PO4]

(e) SiC

(f) Rb

(g) I2

(h) LiBr

(i) P4

(j) Si

(k) Plastic

31. In terms of band theory, what is the difference between

(a) a conductor and an insulator.

(b) a conductor and a semiconductor.

32. Classify the following as amorphous or crystalline solids:

Polyurethane, naphthalene, benzoic acid, Teflon, potassium nitrate, cellophane, Polyvinyl chloride, fibre, glass, copper

33. Sodium crystallized in the cubic lattice and the edge of the unit cell is 430 pm. Calculate the number of atoms in a unit cell.

[Atomic mass of Na = 23.0 u, Density of sodium = 0.9623 gcm–3, NA = 6.023 x 1023 mol–1]

34. Why does table salt, NaCl, sometimes appear yellow in colour?

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35. What type of non-stoichiometric point defect is responsible for the pink colour of LiCl?

36. What type of crystal defect is produced when sodium chloride is doped with MgCl2?

37. Tungsten crystallises in body centred cubic unit cell. If the edge of the unit cell is 316.5 pm, what is the radius of tungsten atom?

Solution

1. How many gram of H2SO4 are needed to prepare 250 ml of 0.2 molar solutions?

2. What is the molarity of solution which contains 18gm of glucose (C6H12O6) in 250 g of H2O?

3. A solution contains 23g of ethanol and 72g of water. Calculate the mole fraction of ethanol and water.

4. Calculate the mole fraction of water in a mixture of 12g water, 108g acetic acid and 92g ethyl alcohol.

5. A solution contains 25% water, 25% alcohol and 50% acetic acid by mass. Calculate the mole fraction of each component.

6. 2.82g of glucose (mol. mass = 180) are dissolved in 30g of H2O. Calculate the

(a) Molality of the solution (b) Mole fraction of glucose and water

7. A bottle of commercial sulphuric acid (density = 1.787g/ml) is labeled as 86% by weight.

(a)What is the molality of the acid?

(b)What volume of the acid has to be used to make 1litre of 0.2M H2SO4?

(c)What is the molality of the acid?

8. Calculate the Molality of 1Msolution of sodium nitrate. The density of the solution is 1.25gcm-3.

9. Why the vapour pressure of a pure liquid is decreased on addition of non volatile solute?

10. Prove that the relative lowering of vapour pressure is equal to the mole fraction of nonvolatile solute in the solution.

11. Explain why freezing point of water is depressed and boiling point is elevated when a non volatile solute is added to it.

12. What is reverse osmosis? Give its one use.

13. The vapor pressure of a dilute aqueous solution of glucose is 750mm Hg at 373K. Calculate the mole fraction of solute. The vapor pressure of pure water is 760mm Hg at 373 K.

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14. Why the osmotic pressure measurement is preferred for the molar mass determination of macromolecules over other colligative properties?

15. When fruits and vegetables that have dried are placed in water; they slowly swell and return to original form, why? Would a temperature increase accelerate the process? Explain.

16.The freezing point of pure nitrobenzene is 278.8K. When 2.5g of unknown substance is dissolved in 100g of nitrobenzene, the freezing point of solution is found to be 276.8K. If the freezing point depression constant of nitrobenzene is 8.0Kkgmol-1. What is the molar mass of unknown substance?

17. One litre aqueous solution of sucrose (molar mass = 342gmol-1) weighing 1015g is found to record an osmotic pressure of 4.82atm at 293K. What is the molality of the sucrose solution?

18. The solubility of Ba(OH)2.8 H2O in water at 288K is 5.6gper 100g of water. What is the molality of the hydroxide ions in the saturated solution of barium hydroxide at 288K? (Atomic Mass: Ba=137, O=16, H = 1).

19. A solution containing 12.5g of a non - electrolyte substance in 175g of water gave a boiling point elevation of 0.70K. Calculate the molar mass of the substance. (Elevation constant for water is Kb=0.52K kgmol-1).

20. Assuming complete dissociation, calculate the expected freezing point of a solution prepared by dissolving 6.0g of Glauber’s salt, Na2SO4.10H2O in 0.10kg of H2O. [Given for water Kf =1.86Kkgmol-1, atomic masses, Na=23, S=32, O=16, H=1 amu].

21. A solution of non volatile solute in water freezes at – 0.30oC. The vapour pressure of pure water at 298K is 23.51mm Hg and Kf for water is 1.86degree/molal. Calculate the vapour pressure of this solution at 298K.

22. State Raoult’s law. State, givingsuitable examples,the factors responsible for the deviations from this law

23. The vapour pressure of pure benzene at 25oC is 639.7mm Hg and the vapour pressure of a solution of a non volatile solute in benzene at the same temperature is 631.9mmHg. Calculate the mole fraction of the solute and molality of the solution (C=12, H=1 ).

24. The vapour pressure of benzene and toluene at 293K are 75mm and 22mm Hg respectively. 23.4g of benzene and 64.4g of toluene are mixed. If the two form an ideal solution, calculate the mole fraction of benzene in vapour phase assuming that the vapours are in equilibrium with the liquid mixture at this temperature.

25. Explain with suitable diagram and appropriate examples why some non ideal solutions show positive and negative deviation from ideal behavior.

26. What is the molar concentration of solute particles in human blood, if the osmotic pressure is 7.2atm at the body temperature of 37oC? (R = 0.0821 Latm K-1 mol-1)

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27. As aqueous solution of glucose is made by dissolving 10 g of glucose (C6H12O6) in 90g of water at 303K. If the vapour pressure of pure water at 303K be 32.8mmHg, what would be the vapour pressure of solution?

28. On dissolving 3.24g of sulphur in 40g of benzene boiling point of solution was higher than that of benzene by 0.81K. Kb value for benzene is 2.53Kkgmol-1. What is the molecular formula of sulphur? (Atomic mass of sulphur=32 gmol-1).

29. To 500 cm3 of water, 3.0 x 10-3 kg of acetic acid is added. If 23% of acetic acid is dissociated, what will be the depression in freezing point? Kfand density of water are 1.86Kkg-1mol-1 and 0.997gcm-3 respectively.

30. An aqueous solution of sodium chloride is marked 10% (w/w) on the bottle. The density of the solution is 1.071gL-1. What is its molality and molarity? Also calculate the mole fraction of each component in the solution.

31. The partial pressure of ethane over saturated solution containing 6.56x10-2 g of ethane is 1bar. If the solution contains 5.0x10-2g of ethane, then what shall be the partial pressure of a gas?

32.The vapour pressure of pure benzene at a certain temperature is 0.850bar. 0.5g Non electrolyte and non volatile solid is added to 39.0g of benzene (Mol. Mass 78gmol-1). The vapour pressure of this solution is found to be 0.845bar. Calculate the molecular mass of the substance.

33. 2g of benzoic acid dissolved in 25g of benzene shows a depression in freezing point equal to 1.62K. Molar depression constant for benzene is 4.9Kkgmol-1. What is the percentage associated of acid if it forms double molecule (dimer) in solution?

34. The molar freezing point depression constant of benzene (C6H6) is 4.90K kgmol-

1.Selenium exits as a polymer of the type Sex. When 3.26g of selenium is dissolved in 226g of benzene, the observed freezing point is 0.112oC lower than for pure Benzene. Deduce the molecular formula of selenium (At. Mass of Se = 78.8g mol-1).

35. Discuss the various types of plots between the partial vapour pressures and the mole fractions of two components of the completely miscible liquids in a solution.

36.What is Osmotic Pressure? How would you determine the molecular mass of solute with the help of osmotic pressure?

OR

Define the term osmotic pressure. Is osmotic pressure of a substance a colligative property? Explain.

37. What is the relation between Vant Hoff’s factor and

(a)degree of association of solute?

(b)degree of dissociation of solute?

(c)If the Vant Hoff’s factor of CaCl2 is 1.5, calculate the degree of dissociation.

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(d)K3[Fe(CN)6] is dissociated 30% in solution. Calculate the Vant Hoff’s factor.

38. Calculate the mole fraction of ethylene glycol (C2H6O2) in a solution containing 20% of C2H6O2 by mass.

39. Calculate the molarity of a solution containing 5g of NaOH in 45 mL solution.

40. Calculate the molality of 2.5g of ethanoic acid (CH3COOH) in 75g of benzene.

41. Calculate the mass percentage of benzene (C6H6) in carbon tetrachloride (CCl4) if 22g of benzene is dissolved in 122g of carbon tetrachloride.

42. The air is a mixture of a number of gases. The major components are oxygen and nitrogen with approximate proportion of 20% is to 79% by volume at 298K. The water is in equilibrium with air at a pressure of 10atm. At 298K if the Henry’s law constants for oxygen and nitrogen at 298K are 3.30x107mm and 6.51 x 107mm respectively. Calculate the composition of these gases in water.

43. Give reasons for the following:

(a) At higher altitudes, people suffer from a disease called anoxia. In this disease they become weak and can’t think clearly.

(b) When mercuric iodide is added to an aqueous solution of KI, the freezing point is raised.

44. 0.6ml of acetic acid (CH3COOH) having density 1.06g mL-1, is dissolved in 1litre of water. The depression in freezing point observed for this strength of acid was 0.0205oC. Calculate the Van’t Hoff factor and dissociation constant of acid.

45. Discuss the Raoult’s law for two miscible volatile liquids.

OR

Explain Raoult’s law in its general form in reference to solutions.

OR

Draw a suitable labeled diagram to express the relationships for ideal solution A and B between vapour pressure and mole fractions of components at constant temperature.

46. Miscible liquid pairs often show negative or positive deviation from Raoult’s law. What is the reason for such deviations? Give one example of each type of liquid pairs.

47. State and define the Henry’s law. Give its limitations and applications also.

OR

State Henry’s law about partial pressure of a gas in mixture.

OR

What is the effect of a pressure of a gas on its solubility in a solvent?

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OR

State Henry’s law and mention its some important applications.

48. Determine the amount of CaCl2 (i = 2.47) dissolved in 2.5 litre of water such that its osmotic pressure is 0.75 atm at 270C.

Electrochemistry

1. Define conductivity and give its units. How it varies with dilution?

2. Define molar conductivity. Write its units. How it varies with dilution?

3. Draw curves to show how the molar conductance of strong electrolytes varies with dilutions.

4. Define Kohlrausch’s law and write its uses.

5. Explain the working of galvanic cell.

6. How does the electrochemical cell differ from electrolytic cell?

7. How Kohlrausch’s law is used to determine the degree of ionization of weak electrolyte?

8. For the cell Zn/Zn2+(aq) || Cu2+(aq)/Cu, derive the relation between Eocell and Kc at 298

K.

9. What is normal hydrogen electrode? Discuss its uses?

10. Depict the electrochemical cell and calculate the E° for each cell

(a) 2Ag+(aq) + Cd2Ag + Cd2+(aq)

(b) Cl2(g) +2I-(aq) 2Cl-(aq) + I2(s)

Given E°Ag+

/Ag = 0.80V, E°Cd2+

/Cd = -0.40V

E°Cl2/Cl-= 1.36V , E°I2/I- = 0.54V

11. For the standard cell, Cu /Cu2+ ll Ag+/Ag

Given E°Cu2+

/Cu =0.34V, E°Ag+

/Ag = 0.80V

(a) Identify cathode and anode as the current is drawn through the cell.

(b) Write the reaction taking place at the electrode.

(c) Calculate the standard cell potential.

12. Discuss the working of fuel cell.

OR

Give an example of a fuel cell and write the anode and cathode reactions for it.

13. Calculate the equilibrium constant for the reaction

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Zn + Cd2+(aq) Zn2+(aq) + Cd (E°Cell =0.36V)

14. Calculate the number of coulombs required to deposit 40.5g Al when the electrode reaction is Al3+ + 3e— Al.

15. Calculate the pH of the following half cell reactions:

Pt – H2 (1atm) /HCl E = 0.25V

16. Chromium metal can be plated out from an acidic solution containing CrO3, according to the following equation:

CrO3 + 6H+ + 6e- Cr + 3H2O

Calculate

(a) how many grams of chromium will be plated out by 24000 coulomb?

(b) how long will it take to plate out 1.5g of cr by using 12.5 ampere current?

17. What is dry cell? Discuss its working.

18. Calculate the equivalent conductivity of 1M H2SO4 solution, if its conductivity is 26x10-2 ohm-1cm-1.

19. Electrolytic conductivity of 0.20 molL-1 solution of KCl at 298 K is 2.48 x 10-2 ohm-

1cm-1. Calculate its molar conductivity.

20. How many coulombs are required to produce?

(a) 20.0 g of calcium from molten CaCl2

(b) 50 g of aluminium from molten Al2O3

21. A solution of nickel nitrate, Ni(NO3)2, is electrolyzed between platinum electrodes using a current of 5.0 ampere for 30 minutes. What weight of Ni will be produced at cathode?

22. What is galvanization? How the corrosion of iron is prevented by galvanization?

23. Three electrolytic cells A, B and C, containing electrolytes zinc sulphate, silver nitrate and copper sulphates respectively, were connected in series. A steady current of 1.5 amps was passed through them, until 1.45 g of silver were deposited at the cathode of cell B.

(a)How long did the current flow?

(b)What weights of copper and zinc were deposited?

24. Calculate the molar conductivity at infinite dilution of acetic acid from the following data:

Λ∞m(HCl) = 426 ohm-1 cm2 mol-1,

Λ∞m(CH3COONa)= 91 ohm-1 cm2 mol-1

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Λ∞m(NaCl)= 126 ohm-1 cm2 mol-1.

25. Calculate the equilibrium constant of reaction at 25°C:

Ni(s) + Cu2+ (aq) Cu(s) + Ni2+(aq)

Given E°Ni2+

/Ni =-0.25V, E°Cu2+

/Cu = +0.34V, R=8.314JK-1 Mol-1, F=96500CMol-1

26. Calculate the equilibrium constant for the reaction at 298K:

Cu(s) + Cl2(g) CuCl2(aq)

Given E°Cu2+

/Cu = 0.34V, E°Cl2/Cl-=1.36V, R=8.314JK-1 Mol-1, F=96500CMol-1

27. Calculate the standard free energy change for the reaction occurring in the cell:

Zn(s) / Zn2+(1M) ll Cu2+(1M) / Cu(s)

[Given E°Zn2+

/Zn =-0.76V,E°Cu2+

/Cu =+0.34V, F=96500CMol-1], How is it related to equilibrium constant for the rection?

28. Calculate the potential (emf) of the cell

Cd I Cd2+(0.10M) II H+(0.20M) I Pt,H2(0.5atm.)

(given E°Cd2+/Cd = -.403V, R=8.314JK-1 Mol- , F=96500CMol-1]

29. Write Nernst equation and find out the e.m.f of the following cells at 25°C,

Pt , Br2(1) I Br- =(0.010M) II H+ (0.030M) I H2(1atm) ,Pt

(E°Br2/2Br- =+1.08V, R=8.314JK-1 Mol- , F=96500CMol-1

30. Calculate the equilibrium constant K for the reaction at 298K.

3Sn4+ + 2Cr 3Sn2+ + 2Cr3+

( given E°Sn4+

/Sn2+=0.15V; E°Cr

3+/Cr=-0.74V)

31. Calculate ∆G° for the reaction

Cu2+(aq) + Fe (s) Fe2+(aq) + Cu(s)

(given E°Cu2+

/Cu = 0.34V, E°Fe2+

/Fe = -0.44V; F=96500CMol-1)

32. State reasons for the following:

(a)Rusting of iron is said to be an electrochemical phenomenon.

(b)For a weak electrolyte, its molar conductance in dilute solution increases sharply as its concentration in solution is decreased.

33. Calculate the emf ∆G for the cell reaction at 25°C for the cell:

Zn(s) I Zn2+(0.0004M) II Cd2+(0.2M) I Cd(s)

E° values at 25°C : Zn2+/Zn =-0.763V; Cd2+/Cd =-0.403V;

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R=8.314JK-1 Mol- , F=96500CMol-1

34. Calculate the emf and ∆G of the cell reaction for the following cell at 25°

Mg(s)/ Mg2+(0.001M) ll Cu2+ (0.0001M) / Cu(s)

E° values: Mg2+/Mg =-2.37V;Cu2+/Cu =+0.34V and , F=96500CMol-1

35. Describe the characteristics of variation of molar conductivity with dilution for

(a) a weak electrolyte and (b) a strong electrolyte.

How are these explained qualitatively?

36. The emf of a cell corresponding to the reaction

Zn + 2H+ Zn2+(0.1M) + H2(1 atm) is 0.28 V at 250C. Write the half cell reactions and calculate pH of solution of hydrogen chloride solution.

37. Resistance of conductivity cell filled with 0.1 mol/L KCl solution is 100 ohm. If resistance of same cell when filled with 0.02 mol/L KCl solution is 520 ohm, calculate the conductivity and molar conductivity of 0.02 mol/L KCl solution. The conductivity of 0.1 mol/L KCl solution is 1.29 S/m.

38. Express the relation among cell constant, resistance of solution in cell and conductivity of solution. How is molar conductivity of solution related to its conductivity.39. Define limiting molar conductivity.40. Why it is not possible to determine Ʌ0m for a weak electrolyte.41. Write the reactions of lead storage battery during recharging.42. At 291K, the molar conductivity at infinite dilution of NH4Cl, NaOH and NaCl are 129.8, 217.4 and 108.9 Scm2/mol respectively. If molar conductivity of centinormal solution of NH4OH is 9.33 Scm2/mol, what is percentage dissociation constant of NH4OH also.

Chemical Kinetics

1. What do you mean by order of reaction? How it is different from molecularity?

2. Derive the general expression for the rate constant K, for the first order reaction using integrated rate law method.

3. For a first order reaction, it takes 5 min. for the initial concentration of 0.6 mol/L to become 0.4 molL-1. How long in all, it takes for initial concentration to become 0.3 mol/L.

4. Show that the time required for the completion of ¾ th reaction of first order is twice the time required for completion of ½ of the reaction.

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5. If half-life of a first order reaction involving reactant A is 5 min. How long will it take [A] to reach 25% of its initial concentration?

6. For the following reaction, the rate law has been determined to be rate = k [A] [B]2 with k = 2.0 x10-6 mol-2L2sec-1.

2A+B+C A2B+C, for this reaction determine the initial rate of reaction with [A] = 0.1 molL-1, [B] = 0.2 molL-1 and [C] = 0.8 molL-1.

Determine the rate after 0.04 molL-1 of A has reacted.

7. Write the Arrhenius equation. How the value of activation energy is determined graphically?

8. How the value of activation energy is calculated from the rate constants of two different temperatures. If the value of activation energy is 50 kJ/mol, show that by increasing the temperature from 300 K to 310 K rate constant become nearly double.

9. If the rate constant of a reaction is 2 mol-1Ls-1 at 700 K and 32 mol-1Ls-1 at 800 K, what is the activation energy?

10. A first order reaction is 50% complete in 30 minutes at 27°C & in 10 minutes at 47°C. Calculate the rate constants at 27°C and 47°C, and the energy of activation of the reaction in kJ/mol.

11. Two reactions (i)A Product (ii)B Product follow first order kinetics. The rate of reaction (i) is doubled when the temperature is raised from 300 K to 310 k. The half-life of this reaction at 310 K is 30 min. At the same temperature B decomposes twice as fast as A. If the activation energy for the reaction (ii) is half than that of reaction (i), calculate the rate constant of the reaction (ii) at 300K.

12. Mention the factors that affect the rate of a chemical reaction.

13. In a pseudo first order hydrolysis of ester in water the following results were obtained:

t/s 0 30 60 90[Ester]/M 0.55 0.31 0.17 0.085

(a) Calculate the average rate of reaction between time interval 30 to 60 second.

(b) Calculate the pseudo first order rate constant for the hydrolysis of ester.

14. A reaction is first order in A and second order in B.

(a)Write differential rate equation.

(b)How is the rate affected when the concentration of B is tripled?

(c)How is the rate affected when the concentration of both A and B are doubled?

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15. For a reaction 2I- + 2H+ I2 (s) + H2(g) , if the initial concentration of I- was 0.80 molL-1 and concentration after 20 minutes was 0.68 mol lit-1. Calculate the rate of disappearance of I- and rate of appearance of I2 .

16. The reaction N2O5 2 NO2 + ½ O2 is of first order with respect to N2O5. Its rate constant is 6.2x10-6s-1, if in the beginning [ N2O5] is 15 molL-1, calculate the rate of reaction in the beginning.

17. For a chemical reaction, variation in concentration Ln[A] vs time (min) plot is shown alongside.

(a) What is the order of the reaction?(b) What are the units of rate constant, k for the reaction?

18. What is the effect of adding catalyst on G of reaction? Δ

Surface Chemistry

1. What is the effect of the pressure of the gas on adsorption?

2. Discuss the effect of temperature on adsorption.

3. What is the difference between hydrophobic (lyophobic) and hydrophilic (lyophillic) sols? Give one example of each.

4. Distinguish between multimolecular and macromolecular colloids. Give one example of each type.

5. Write a short note on associated colloids and micelles. How associated colloids are different from multimolecular and macromolecular colloide?

6. Write short notes on: (i) Peptization, (ii) Mechanical dispersion.

7. How the solutions of sols are purified? Discuss the process of dialysis.

8. Explain what is observed (i) a beam of light is passed through a colloidal solution,

(ii) an electric current is passed through a colloidal solution.

9. Write short notes on : (i) Brownian movement, (ii) Hardy and Schultz rule.

10. What are emulsions? What are their different types? Give an example of each type.

11. Give two applications of colloids.

12. Discuss the activity and selectivity aspects of solid catalysts.

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13. Describe the cleaning action of soaps and detergents?

14. Why is adsorption always exothermic?

15. Physical and Chemical adsorption respond differently to rise in temperature. What is this difference and why is it so?

16. Give reason why a finely divided substance is more effective as an adsorbent.

17. What are the factors which influence the adsorption of a gas on solid?

18. Discuss Langmuir adsorption isotherm. Distinguish between Freundlich isotherm and Langmuir adsorption isotherm.

19. Describe a chemical method each for the preparation of sols of sulphur and platinum in water

20. What is demulsification? Name two techniques for demulsification.21. (a) Describe a method for distinguishing a colloidal solution for a true solution when the two have the same colour.

(b) When are gas masks used and how do they work?

(c) What is meant by shape selective catalyst?

22. Differentiate between emulsions and micelles taking a suitable example of each.

23. What are enzymes? Describe the mechanism of enzyme catalysis.

24. Distinguish between physisorption and chemisorption.

25. Discuss shape selective catalysis.

26. What are enzymes? Describe the mechanism of enzyme catalysis.

27. Explain the following observations:(a) Ferric hydroxide sol gets coagulated on addition of sodium chloride solution.(b) Cottrell’s smoke precipitator is fitted at the mouth of the chimney used in factories.(c) Physical adsorption is multilayered, while chemisorption is monolayered.

28. Which one of the following electrolytes is the most effective for the coagulation of Fe(OH)3 sol and why? NaCl, Na2SO4, Na3PO4

29. (a) Adsorption of a gas on the surface of solid is generally accompanied by a decrease in entropy still it is a spontaneous process. Explain.(b) How does an increase in temperature affect both physical as well as chemical adsorption?30. What is electrodialysis? What happens when dialysis is prolonged?

31. Why is ferric chloride preferred over potassium chloride in case of a cut leading to bleeding?

32. How can a lyophilic sol be coagulated?33. What is Kraft temperature?

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34. How does a delta form at the meeting place of sea and river water?35.Give one example of positively charged sol and one example of negatively charged sol.36. What happens in the following activities and why?(a) An electrolyte is added to a hydrated ferric oxide sol in water. (b) A beam of light is passed through a colloidal solution.(c) An electric current is passed through a colloidal solution.38. How do size of particles of adsorbent, pressure of gas and prevailing temperature influence the extent of adsorption of a gas on a solid?39. Do the vital functions of the body such as digestion get affected during fever? Explain your answer.40. Explain the following observations:(a) Lyophilic colloid is more stable than lyophobic colloid.(b) Coagulation takes place when sodium chloride solution is added to a colloidal solution of ferric hydroxide.(c) Sky appears blue in color.

41. (a) What are micelles? How do they differ from ordinary colloidal particles? Give two examples of micelle forming substances.(b) State Hardy-Schulze rule.42. Explain how the phenomenon of adsorption finds application in each of the following processes:(a) Production of vacuum(b) Heterogeneous catalysis(c) Froth floatation process43. Discuss the effect of pressure and temperature on the adsorption of gases on solids.

Coordination Compounds

1. What are double salts and coordination compounds?2. What are inner orbital complexes and outer orbital complexes? Give examples.3. Show that all octahedral complexes of Ni2+ must be outer orbital complexes.4. According to Werner’s theory, how many types of valencies are shown by a central metal atom?5.What would be the shape of the complex if it is formed after (i)sp3 (ii) dsp2 (iii) d2sp3(iv) sp3d2hybridization? Give one example.6. Give IUPAC names:(i)[Co(NH3)4.NO2.Cl]NO3

(ii)Cu2[Fe(CN)6](iii)K[PtCl3(NH3)](iv)[Cr(NH3)6]3+

(v) [Co(en)2Cl(ONO)]+

(vi)[Pt(NH3)4Cl2][PtCl4](vii)K3[Cr(C2O4)3](viii)[Cr(NH3)3Cl3](ix)[PtCl(NH3)5]Cl3

(x)[CoCl2(NH3)4]+

(xi)[PtBrCl(NO2)NH3]-

7. Define cis and trans isomerism in complexes giving examples.8. Why?(a) [Ti(H2O)6]3+ is colored while [Sc(H2O)6]3+ is not.

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(b) [Fe(CN)6]3- is weakly paramagnetic while [Fe(CN)6]4- is diamagnetic.(c) [Ni(CO)4] possesses tetrahedral geometry while [Pt(NH3)2Cl2] is square planar.(d)Tetrahedral Ni (II) complexes are paramagnetic but square planar Ni (II) complexes are diamagnetic.9. Using valence bond approach, predict the shape and magnetic character of [Fe(CN)6]3-

[Co(NH3)6]3+ , [Ni(CN)4]2-, [Ni(NH3)6]2+ , [NiCl4]2-, [Ni(CO)4].10. Mention the application of coordination compounds in the following areas, giving example(a)Analytical chemistry (b)extraction of metals11. Discuss optical isomerism in complexes.12. Give importance of coordination compounds in industry and chemotherapy.13. Draw structures and write the hybridization of atomic orbital of transition metals:(a) [Fe(CO)5](b)[Co(NH3)6]3+

(c)[NiCl4]2-

(d)[Co(NH3)6]3+

(e)[Ni(CN)4]2-

(f)[Ni(CO)4]

14. Describe the nature of bonding in metal carbonyls.15. Draw figures to show splitting of degenerate d-orbital in an octahedral and in a tetrahedral crystal field.16.Find out the oxidation states of metal ion marked by asterisk (*) in the following:(a)[Co*(NH3)2(NO2)Cl][Au(CN2)](b) [Pt*(NH3)2Cl2]Cl2

(c)[Co*(NH3)4(H2O)Br](NO3)2

17. Select a complex formation and write an expression for the stability constant of the complexes species. What information is conveyed regarding the strengths of ligand from the stability constant values of their complexes with a metal ion? Illustrate by giving example of monodentate ligand.18. Explain how [Pt(NH3)2Cl2] and [Pt(NH3)6]Cl4 will differ in their electrolyticconductance? Give the hybridization states of Pt in these complexes.19. Giving a suitable example describe the importance of the formation of complexes in:(a)The estimation of hardness of water.(b)The extraction of a particular metal from its natural source.20. Explain geometrical isomerism with reference to square planar complexes giving examples. How the tetrahedral complexes with simple ligands do not exhibit geometrical isomerism?21. Designate the coordination entities, oxidation state of metal and counter ions in the following:(a)K3[Fe(CN)6](b)[Cr(NH3)6]Cl3

(c)[Ni(CO)4](d)K2[PtCl6]22. Draw structures and find out chiral one (optically active)?cis-[CrCl2(OX)2]3-and trans-[CrCl2(OX)2]3-

23. Using IUPAC norms, write formulae:

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(i)Hexaammineplatinum(IV)(ii)Hexaamminecobalt(III)sulphate(iii)Potassiumtetracyanonickelate(II)(iv)Potassiumtetrachloridopalladate(II)(v)Tetrabromidocuprate(II)(vi)Pentaamminrnitrito-O-Cobalt(III)(vii)Pentaamminrnitrito-N-Cobalt(III)(viii)Diaamminechlorido(methyl amine)platinum(II)chloride(ix)Hexaammineplatinum(IV)(x)Tetrahydroxozincate(II)(xi)Pentaaquachloroidochromium(III)chloride(xii)Pentacarbonyliron(0)(xiii)Amminedichlorido(pyridine)platinum(II)(xiv)Diamminechlorido(methylamine)platinum(II)chloride

24. Sketch the geometrical shapes:(i)dsp2

(ii)dsp3

(iii)d2sp3

(iv)sp3