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 + NH₄OH solution | Reddish-brown precipitate | Group-III cation may be present |
| Confirmatory Tests | ||
| Potassium Ferrocyanide Test Dissolve the precipitate in dilute HCl, divide into two parts and add potassium ferrocyanide to one part | Blue/Prussian blue precipitate | Fe³⁺ is confirmed |
| Potassium Thiocyanate Test To second part add potassium thiocyanate solution | Blood-red colouration is formed | Fe³⁺ is confirmed |
The given salt contains Fe³⁺ ions as cation and Cl⁻ ions as anion. The salt is Fe(Cl)₃.