Qualitative Analysis of Sulphide Ion

Sulphide ion (S^2–) can be detected by treating a salt with dilute H₂SO₄.

Observation

Colourless gas with suffocating smell of rotten eggs is given out.

MS + H₂SO₄ → MSO₄ + H₂S (Hydrogen sulphide)

Confirmatory Test

Filter paper moistened with lead acetate turns black on exposure to gas.

Ph(CH₃COO)₂ + H₂S → 2CH₃COOH + PbS (Black lead Sulphide)

Sodium Nitroprusside Test

A violet colouration is obtained on adding freshly prepared solution of sodium nitroprusside to salt solution.

Na₂S + Na₂[Fe(NO)(CN)₅] → Na₂[Fe(CN)₅NOS]