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 + Dilute HCl | No reaction | Group I cation is absent |
| Original solution + Dilute HCl + H₂S gas (with NH₄Cl) | No reaction | Group II cation is absent |
| Original solution + Dilute HCl + NH₄Cl solid + NH₄OH | No reaction | Group III cation is absent |
| Original solution + NH₄Cl + NH₄OH + (NH₄)₂CO₃ | White ppt is formed | Group V cation may be present |
| Confirmatory Tests | ||
| Flame Test Moisten the salt with conc. HCl and introduce it into a non-luminous flame on a platinum / nichrome wire | Apple-green flame | Ba²⁺ is confirmed |
| Potassium Chromate Test Dissolve the white precipitate in dilute acetic acid and add potassium chromate | Yellow precipitate of barium chromate | Ba²⁺ is confirmed |
The given salt contains Ba²⁺ as the cation (basic radical) and SO₃²⁻ as the anion (acidic radical). The salt is Barium Sulphite (BaSO₃).