To determine the presence of anion and cation in the given salt
| Experiment | Observation | Inference |
|---|---|---|
| Take 0.1 g of salt and add conc. H₂SO₄ | A colourless gas is evolved which gives dense white fumes with ammonia | Cl⁻ may be present |
| Confirmatory Tests | ||
| Concentrated H₂SO₄ and MnO₂ Test Take a pinch of MnO₂ in salt solution and add 3–4 drops of conc. H₂SO₄, then heat | Greenish yellow chlorine gas is evolved | Presence of Cl⁻ is indicated |
| Silver Nitrate Test Acidify 1 mL of sodium carbonate extract with dilute HNO₃ (or use water extract) and add AgNO₃ solution | Curdy white precipitate soluble in NH₄OH | Cl⁻ is confirmed |
| Chromyl Chloride Test Take a little salt with solid K₂Cr₂O₇, add conc. H₂SO₄, heat. Pass the evolved gas through sodium hydroxide solution, divide into two parts. Acidify one part with acetic acid and add lead acetate solution | The sodium hydroxide solution becomes yellow; adding acetic acid and lead acetate gives yellow precipitate of lead chromate | Cl⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + Dil. HCl + NH₄Cl solid + NH₄OH | White gelatinous precipitate | Al³⁺ may be present |
| Confirmatory Tests | ||
| Dissolve white precipitate in dilute HCl and divide into two parts | To the first part, add sodium hydroxide and warm. A white gelatinous precipitate dissolves in excess sodium hydroxide solution | Aluminium is confirmed |
| Blue Lake Test To the second part, add few drops of blue litmus solution and then NH₄OH dropwise along the sides of the test tube | A blue floating mass appears in colourless solution | Presence of Al³⁺ is confirmed |
The given salt contains Al³⁺ ions as cation and Cl⁻ ions as anion. The salt is Al(Cl)₃.