To determine the presence of anion and cation in the given salt
| 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 |
|---|---|---|
| Take 0.1 g of salt and add 1–2 mL of NaOH solution, then heat | A smell of ammonia is evolved | NH₄⁺ may be present |
| Bring a glass rod dipped in hydrochloric acid near the mouth of the test tube | Dense white fumes are observed | NH₄⁺ may be present |
| Confirmatory Test | ||
| Nessler's Reagent Test Pass the evolved gas through Nessler’s reagent | Brown colouration or a brown precipitate of basic mercury(II) amido-iodide is obtained | Presence of NH₄⁺ is confirmed |
The given salt contains NH₄⁺ ions as cation and C₂O₄²⁻ ions as anion. The salt is (NH₄)₂C₂O₄.