Question

Explain about the oxidation test for sulphur.

Answer 1

1. Oxidation test:

The organic substances are fused with a mixture of KNO₃ and Na₂CO₃. The sulphur if present is oxidised to sulphate.

Na₂CO₃ + S + 3(O) Na₂SO₄ + CO₂

2. The fused mass is extracted with water, acidified with HCl and the BaCl₂ solution is added to it. A while precipitate indicates the presence of sulphur.