To determine the presence of anion and cation in the given salt
| Experiment | Observation | Inference |
|---|---|---|
| Take 0.1 g of salt, add 1–2 mL of dilute H₂SO₄ | Colourless odourless gas is evolved with brisk effervescence; lime water turns milky | CO₃²⁻ may be present |
| Confirmatory Tests | ||
| Lime Water Test Pass the gas through lime water | Lime water turns milky; milkiness disappears on excess gas | CO₃²⁻ is confirmed |
| Sodium Nitroprusside Test Take 1 mL water extract or sodium carbonate extract, make it alkaline with dilute NH₄OH, then add a drop of sodium nitroprusside | Purple or violet colouration is produced | CO₃²⁻ 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 CO₃²⁻ ions as anion. The salt is (NH₄)₂CO₃.