10th Class Chapter No 23 - Sulphuric Acid in science for ICSE

Properties of Sulphuric Acid:

• Sulphuric Acid has molecular formula H₂SO₄and molecular mass of 98.
• Sulphuric acid is called 'King of Chemicals' because of its extensive use in a large number of industries.
• Sulphuric acid is a powerful protonating agent.
• It is also a moderately strong oxidising agent.
• Sulphuric acid is also a powerful dehydrating agent and is used to remove a molecule of water from many organic compounds.
• Sulphuric Acid, H2SO4, is a dibasic acid because it contains two hydrogens atoms which ionise in aqueous solution to become Hydrogen Ions, H(+).

H2SO4    ==>    2 H(+)    +    SO4(2 -)

Preparation of Sulphuric Acid:

The Contact Process is used for manufacturing sulphuric acid and fuming sulphuric acid from sulphur dioxide, which is made by burning sulphur or by roasting sulphide ores and oxygen (in the form of air) which combine to form sulphur trioxide in the presence of a catalyst.

Manufacture of Sulphuric Acid by Contact process

Sulphuric acid is produced from sulphur, oxygen and water via the conventional contact process or the wet sulphuric acid process (WSA).

The Contact process can be divided into five stages:

1. Combining of sulphur and dioxygen (O₂) to form sulphur dioxide
2. Purifying the sulphur dioxide in a purification unit
3. Adding an excess of dioxygen to sulphur dioxide in the presence of the catalyst vanadium pentoxide, under temperatures of 450 °C and pressure of 1-2 atm
4. The sulphur trioxide formed is added to sulphuric acid which gives rise to oleum(disulphuric acid)
5. The oleum is then added to water to form sulphuric acid which is very concentrated.

There are mainly two types of tests are performed for Sulphuric Acid

1. Test for Dilute sulphuric acid.
2. Test for Concentrated sulphuric acid.

Uses of sulphuric acid

1. Sulphuric acid, because of its wide applications, is referred as the king of chemicals.
2. It is used in the manufacture of:

• Fertilisers like ammonium sulphate and superphosphate.
• Dyes, pigments and paints.
• Explosives such as TNT.
• Other important chemicals like hydrochloric acid, nitric acid, phosphoric acid and sodium carbonate.

3. It is used in the refining of petroleum.
4. As a pickling agent.
5. As a laboratory agent, and a dehydrating and oxidising agent.