Sulphur(IV) Oxide (SO₂)

Topic Content:

Preparation of Sulphur(IV) Oxide (SO₂ ):

In the industries, sulphur(IV) oxide is produced by burning sulphur or metallic sulphide in oxygen. The gas is liquefied under high pressure and sold as liquid stored in a steel cylinder. i.e.

S_(s) + O_2(g) → SO_2(g)

or

4FeS_2(s) + 11O_2(g) → 2Fe₂ O_3(s) + 8SO_2(g)

In the laboratory, sulphur(IV) dioxide is prepared by the reaction of potassium or sodium trioxosulphate(IV) with tetraoxosulphate(VI) acid or hydrochloric acid. For example, a reaction between the dilute tetraoxosulphate(VI) acid with sodium trioxosulphate(IV) produces SO₂ .

Na₂ SO₃  + H₂ SO₄   → Na₂ SO₄   + H₂ O + SO₂