Sulphuric acid

• Sulfuric acid or sulphuric acid is a mineral acid composed of the elements sulfur, oxygen and hydrogen.

Oxides of Sulphur

• There are two main oxides of Sulphur

  • Sulphur Dioxide (So2): gas formed when sulphur burns in air

  • Sulphur trioxide(So3): involves the catalytic oxidation of sulphur dioxide which is carried out industrially in the Contact process.

Industrial manufacture of Sulphuric acid

• Preparation of sulphur dioxide.

• .Conversion of sulphur dioxide into sulphur trioxide.

• Conversion of sulphur trioxide formed into concentrated H2SO4.

• Step 1: Preparation of sulphur dioxide:

• SO2 is prepared by burning sulphur in the presence of excess air so that the product combines with oxygen which is helpful for the next stage.

• S(s) + O2 (g) → SO2(g)

• Step 2: Preparation of sulphur trioxide:

• Sulphur trioxide is formed when sulphur dioxide reacts with oxygen in a ratio of 1:1

• at a temperature of 400 °C – 450°C

• and a pressure of 1-2 atm in the presence of V2O5 as a catalyst.

• This reaction is reversible in nature.

• 2SO2(g) + O2(g) ⇌ 2SO3(g)

• Step 3: Preparation of concentrated sulphuric acid:

• The sulphur trioxide formed is first made to react with concentrated sulphuric acid.

• H2SO4 + SO3(g) → H2S2O7(l)

• H2S2O7(l) + H2O(l) → 2H2SO4

Uses of Sulphuric Acid

• In Industries:

  • used in the production of phosphoric acid which is in turn used to make phosphate fertilizers.

  • It is used in the manufacturing of metals such as copper, zinc etc.

  • making of fibres.

  • Used in acidic drain cleaners.

  • Used as a catalyst in the manufacturing process of nylon.

  • Used in the Manheim process in the manufacturing of HCl.

• Used in petroleum refining.

Acid rain

• Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air.

• These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.