The king of acids- H2SO4

A presentation by-•Ruth Daniels (1830)

•Vandana Vashisth(1831) Dimpy Chugh (1833)•Drishti Bhalla (1838)

INTRODUCTION

•Sulphuric acid is a highly corrosive strong mineral acid with the molecular formula H2SO4.•It is a pungent, colorless slightly yellow viscous liquid which is soluble in water at all concentrations. •Sometimes, it is dyed dark brown during production to alert people to its hazards. •It is an oxidising agent and a dehydrating agent.• It freezes at 283k and boils at 611k .•ST. LOUIS, MO (February 1999) -- Monsanto Enviro-Chem Systems, Inc. has completed the construction and startup of the largest single train sulphuric acid plant in the world.

STRUCTURE OF H2SO4

Contact process It is the method used to manufacture

sulphuric acid needed for industrial processes

METHOD

• Combining of sulphur and oxygen• Purifying sulphur dioxide in the purification unit;• Adding excess of oxygen to sulphur dioxide in presence

of catalyst vanadium oxide, (temp - 450 degrees Celsius and pressure of 1-2 atm) to form sulphur trioxide,

• The sulphur trioxide formed is added to sulphuric acid which gives rise to oleum (disulphuric acid);

• The oleum then is added to water to form sulphuric acid which is very concentrated.

SO3 is not directly passed in water, because a dense fog of minute particles of H2SO4 is produced(which is highly corrosive). It is therefore, dissolved in conc.H2SO4 to form pyrosulphuric acid (oleum).

Platinum was formerly employed as a catalyst for the reaction, but as it is susceptible to poisoning by arsenic impurities in the sulphur feedstock, vanadium(V) oxide (V2O5) is now preferred. The process can be summarized by the following equations-

S + O2 →SO2

 4FeS2 +11O2 →2Fe2O3 +8SO2    2SO2 +O2 →2SO3 +45 Kcal                          SO3 + H2SO4 → H2S2O7 (OLEUM) H2S2O7 + H2O → 2H2SO4

Why is H2SO4 called the ‘king of acids’?• Sulphuric acid is involved, in some way or the other, in the manufacture of

practically everything.• Certain chemicals, explosives, acids, dyes, glue, wood preservatives,

automobile batteries, fertilizers, and soaps are some of the things manufactured with the help of this acid.

• It is used in the purification of petroleum, the pickling of metal, copper smelting, electroplating, metal work, and the production of rayon and film.

• 60% of all sulphuric acid produced is mixed with crushed phosphate rock to make phosphoric acid which primarily has two uses - to make phosphate fertilizers, and to make sodium triphosphate (a detergent).

• Indeed, the production of sulphuric acid is sometimes used as a measure of how industrially advanced a country is. India produces about 48 lakh tonnes of this acid a year.

New and improved uses for sulphur

One of the most promising uses for sulphur comes from a Shell-patented technology that adds a mix of elemental sulphur and sulphate to fertilisers. Shell Thiogro technology makes sulphur — a vital nutrient for many crops — more readily available to plants throughout the growing season.

The benefits of more effective sulphur use in fertiliser could be significant: tests on crops by Shell and the Sulphur Institute in the USA showed it can increase yields by 14% on average in sulphur deficient soils.

Sulphur is also widely used in the construction industry. For example, adding sulphur pellets to asphalt helps make road surfaces more durable and resistant to extreme high and low temperatures.

PHYSICAL PROPERTIES  Sulphuric acid is a clear, colorless, oily

liquid. Highly corrosive Dehydrating agent Melting Point: 10.35°C Boiling Point: 315-338°C Vapor Density: 3.4 Specific Gravity: 1.84

Chemical propertiesReaction with water •Because the hydration energy of sulphuric acid is highly exothermic , dilution should always be performed by adding the acid to the water rather than the water to the acid. Because the reaction is in an equilibrium that favors the rapid protonation of water, addition of acid to the water ensures that the acid is the limiting reagent. This reaction is best thought of as the formation of hydronium ions:

H2SO4 + H2O → H3O+ + HSO4-

•Because the hydration of sulphuric acid is thermodynamically favorable and the affinity of it for water is sufficiently strong, sulphuric acid is an excellent dehydrating agent. Concentrated sulphuric acid has a very powerful dehydrating property, removing water (H2O)from other compounds including sugar and other carbohydrates and producing carbon , heat, steam, and a more dilute acid containing increased amounts of hydronium and bisulfate ions.

C12H22O11 + H2SO4 → 12 C + 11 H2O + H2SO4

Acid-Base PropertiesAs an acid, sulphuric acid reacts with most bases to give the corresponding sulphate.

CuO(s) +H2SO4(aq) → CuSO4(aq) +H2O(l)Sulphuric acid can also be used to displace weaker acids from their salts.

H2SO4 + CH3COONa →NaHSO4 +CH3COOHSimilarly ,

H2SO4 + KNO 3 →HNO 3 + K2SO4 Reactions with metals and strong oxidising propertyDilute sulphuric acid reacts with metals via a single displacement reaction as with other typical acids , producing hydrogen gas and salts (the metal sulphate).

3Fe(s)+ H2SO4(aq) → H2(g)+FeSO4(aq)

Concentrated sulphuric acid is a strong oxidizing agent and does not react with metals in the same way as other typical acids . Sulfur dioxide , water and SO4

2− ions are evolved instead of the hydrogen and salts.

2H2SO4 + 2e- → SO2 + 2H2O + SO42-

It can oxidize non-active metals such as tin and copper , depending upon the temperature of it like the nitric acid.

Cu + 2H2SO4 → SO2 + 2H2O + SO42− +

Cu2+

Reactions with non-metals Hot concentrated sulphuric acid oxidizes non-metals such as carbon and sulphur .

C + 2H2SO4 → CO2 + 2SO2 + 2H2O S + 2H2SO4 → 3SO2 + 2H2O

•Reactions with sodium chlorideIt reacts with sodium chloride , and gives hydrogen chloride gas and sodium bisulphate.

NaCl + H2SO4 → NaHSO4 + HCl•Electrophilic aromatic substitutionBenzene undergoes electrophilic aromatic substitution with sulphuric acid to give the corresponding sulphonic acids.

Safety first…• Hazard Risks - The common ways a worker can be exposed to

sulphuric acid include contact with the skin or eyes ; inhalation of the acid is also a potential risk, and swallowing sulphuric acid can cause internal damage. Safety procedures should be put into place for any worker who handles sulphuric acid and any group of workers for whom inhalation exposure can occur.

• Always wear protective goggles, gloves and a lab coat, as concentrated H2SO4 causes serious damage to skin and clothing, charring it .

• When diluting H2SO4, add small volumes of the acid to large volumes of water to disperse heat whilst mixing thoroughly. During pouring of the liquid, pouring down the sides prevents splashing.

• Work near a running supply of water. If the acid contacts the skin, it must be washed off rapidly with copious amounts of tap water (however with large spills onto the skin, wipe off excess first).

• Have a supply of neutralizer (sodium carbonate or bicarbonate) in case it is split. It should be first isolated to prevent it spreading and the area evacuated in case of fumes. Sand and a bucket can be used to clear acid for neutralization.

• Store the acid in smaller, easier to handle bottles (<1L). Avoid dribbling acid down the sides of containers, and wipe off any as soon as possible if present. Always place the bottle in a drip tray to ensure that do not contact the bench or shelf.

• Treating Exposures– Any area in which sulphuric acid is used should contain a safety shower, an eyewash 

station and clean chemical suits and gloves as well as emergency respirators.–  If a worker gets the acid on her skin, flush the skin immediately with water and 

remove any clothing that the acid has eaten through to cause the exposure. – If acid gets into a worker's eyes, flush her eyes with water.–  Swallowing sulphuric acid will cause immediate burns to the mouth, esophagus and 

stomach; if this happens, drink large amounts of water to neutralize the acid; however, don't encourage vomiting, which will expose the damaged areas a second time as the acid comes back up. 

– For exposure to fumes, get the worker to fresh air. Get medical help as soon as possible after any type of exposure to sulphuric acid.

• Surface Exposures– In the case of small or large spills of sulphuric acid, two methods can be used for 

cleanup. – Either dilute the acid with water as quickly as possible, or–  use an absorbent material to soak up and neutralize it. – Dry sand, soil or vermiculite are common materials used to absorb sulphuric acid.

Thankyou!