Discuss chemical properties of sulphur dioxide gas.

Chemical properties of sulphur dioxide gas are:

Reaction with gas:

i. When sulphur dioxide gas is passed through the solution of sodium hydroxide, sodium sulphite is formed.

SO₂ + NaOH → Na₂SO₃ + H₂O

Sodium

sulphite

ii. When sulphur dioxide gas is passed through the lime water, lime water becomes milky and calcium sulphite is formed.

SO₂ + Ca(OH)₂→ CaSO₃ + H₂O

Lime Calcium

water sulphite

Reaction with dioxygen gas:

When sulphur dioxide gas is passed through dioxygen gas in the presence of V₂O₅ catalyst, sulphur trioxide is formed.

2SO₂ + O₂→ 2SO₃

Sulphur trioxide

Reaction with hydrogen sulphide gas (H₂S) :

When sulphur dioxide gas is passed through hydrogen sulphide gas, sulphur is formed.

2SO₂ + H₂S → 3S + 2H₂O

Sulphur