Qualitative analysis
How to do salt analysis · Viva · Quiz
To analyse the given inorganic salt for one acidic and one basic radical.
| Experiment | Observation | Inference |
|---|---|---|
| Warm 1 mL of water extract or sodium carbonate extract with dilute H₂SO₄ | Colourless gas with pungent smell of burning sulphur is evolved | SO₃²⁻ may be present |
| Confirmatory Tests | ||
| Barium Chloride Test Add barium chloride to water extract or sodium carbonate extract | White precipitate dissolves on adding dilute HCl and SO₂ is evolved | SO₃²⁻ is confirmed |
| KMnO₄ Decolourisation Test Add dilute H₂SO₄ to the barium sulphite precipitate and then very dilute KMnO₄ solution | Colour of potassium permanganate solution is discharged | SO₃²⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + H₂S gas in presence of NH₄OH | White precipitate is formed | Group IV cation may be present |
| Confirmatory Tests | ||
| Sodium Hydroxide Test Add sodium hydroxide solution dropwise | White precipitate forms and dissolves in excess NaOH on heating | Zn²⁺ is confirmed |
| Potassium Ferrocyanide Test After neutralisation with NH₄OH, add potassium ferrocyanide solution | Bluish-white precipitate | Zn²⁺ is confirmed |
The given salt contains Zn²⁺ as the cation (basic radical) and SO₃²⁻ as the anion (acidic radical). The salt is Zinc Sulphite (ZnSO₃).