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 |
|---|---|---|
| Add conc. H₂SO₄ to the solution and boil with a few copper turnings/chips | On heating, brown fumes (NO₂) are evolved in excess and the solution becomes blue | NO₃⁻ may be present |
| Confirmatory Test | ||
| Brown Ring Test Take 1 mL of salt solution, add 2 mL conc. H₂SO₄, cool, then add freshly prepared ferrous sulphate solution along the sides | Brown ring is formed at the junction of the two solutions | NO₃⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + H₂S gas in presence of dil. HCl and NH₄Cl | Yellow precipitate is formed | Group-II-B (As³⁺) may be present |
| Confirmatory Test | ||
| Ammonium Molybdate Test Treat the dissolved precipitate with concentrated nitric acid and ammonium molybdate solution | Canary yellow precipitate is formed | Presence of As³⁺ is confirmed |
The given salt contains As³⁺ as the cation (basic radical) and NO₃⁻ as the anion (acidic radical). The salt is Arsenic(III) Nitrate (As(NO₃)₃).