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 salt and add conc. H₂SO₄ | Colourless gases are evolved. On testing further, CO₂ and CO are evolved | C₂O₄²⁻ may be present |
| Confirmatory Tests | ||
| Calcium Chloride Test Acidify extract with acetic acid and add calcium chloride | White precipitate of calcium oxalate is obtained | C₂O₄²⁻ is confirmed |
| KMnO₄ Test Filter and add dilute H₂SO₄ to the precipitate, then dilute KMnO₄ and warm | KMnO₄ pink colour is discharged | C₂O₄²⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + H₂S gas in presence of NH₄OH | Black precipitate is formed | Group IV cation may be present |
| Dissolve the black sulphide precipitate in aqua regia and heat | Residue remains in solution after evaporation | Co²⁺ may be present |
| Confirmatory Test | ||
| Potassium Hexanitritocobaltate(III) Test Neutralise with NH₄OH, acidify with dilute acetic acid and add strong potassium nitrite solution | Yellow precipitate is formed | Presence of Co²⁺ is confirmed |
The given salt contains Co²⁺ as the cation (basic radical) and C₂O₄²⁻ as the anion (acidic radical). The salt is Cobalt(II) Oxalate (CoC₂O₄).