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 the salt with dilute H₂SO₄ | Colourless gas with smell of rotten eggs is evolved | S²⁻ may be present |
| Confirmatory Tests | ||
| Lead Acetate Test Pass gas through filter paper dipped in lead acetate solution | Paper turns black | S²⁻ is confirmed |
| Sodium Nitroprusside Test Make solution alkaline with NH₄OH (or sodium carbonate extract) and add sodium nitroprusside solution | Purple/violet colouration is produced | S²⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + Dilute HCl | White precipitate | Pb²⁺ may be present |
| Confirmatory Tests | ||
| Potassium Iodide Test Dissolve one part of the hot precipitate in hot water and add potassium iodide solution | Yellow precipitate is formed | Presence of Pb²⁺ is confirmed |
| Potassium Chromate Test To the acidified solution obtained above, add potassium chromate solution | Yellow precipitate is formed | Presence of Pb²⁺ is confirmed |
| Lead Sulphate Test Dissolve lead sulphide precipitate in dilute HNO₃, then add a few drops of dilute H₂SO₄ and alcohol | White precipitate of lead sulphate is formed | Presence of Pb²⁺ is confirmed |
The given salt contains Pb²⁺ as the cation (basic radical) and S²⁻ as the anion (acidic radical). The salt is Lead(II) Sulphide (PbS).