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 |
|---|---|---|
| Take 0.1 g of salt in a test tube and add conc. H₂SO₄ | Deep violet vapour with a pungent odour is evolved | I⁻ may be present |
| Confirmatory Tests | ||
| Layer Test Take test solution or extract, add CHCl₃/CCl₄ and chlorine water dropwise, then shake vigorously | Violet colouration appears in the organic layer | I⁻ is confirmed |
| Silver Nitrate Test Acidify sodium carbonate extract with dilute HNO₃ and add AgNO₃ | Yellow precipitate is obtained, insoluble in excess NH₄OH | I⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + H₂S gas in presence of dil. HCl | Black precipitate of Group-II A is formed | Group-II cation may be present |
| Confirmatory Tests | ||
| Ammonium Hydroxide Test To the original solution (or the filtrate after dissolving the black ppt in dilute HNO₃) add NH₄OH dropwise, then in excess | Pale blue precipitate of Cu(OH)₂ dissolves in excess NH₄OH giving a deep blue tetraamminecopper(II) solution | Cu²⁺ is confirmed |
| Potassium Ferrocyanide Test Acidify the solution with acetic acid and add potassium ferrocyanide | Chocolate-brown precipitate of copper ferrocyanide | Presence of Cu²⁺ is confirmed |
The given salt contains Cu²⁺ as the cation (basic radical) and I⁻ as the anion (acidic radical). The salt is Copper(II) Iodide (CuI₂).