To determine the presence of anion and cation in the given salt
| Experiment | Observation | Inference |
|---|---|---|
| Warm 1 mL of water extract or sodium carbonate extract with dilute H₂SO₄ | Colourless gas with pungent smell of burning sulphur is evolved | SO₃²⁻ may be present |
| Confirmatory Tests | ||
| Barium Chloride Test Add barium chloride to water extract or sodium carbonate extract | White precipitate dissolves on adding dilute HCl and SO₂ is evolved | SO₃²⁻ is confirmed |
| KMnO₄ Decolourisation Test Add dilute H₂SO₄ to the barium sulphite precipitate and then very dilute KMnO₄ solution | Colour of potassium permanganate solution is discharged | SO₃²⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Salt solution + NaOH solution | Dirty green precipitate | Fe²⁺ may be present |
| Confirmatory Test | ||
| Potassium Ferricyanide Test Add potassium ferricyanide solution | Dark blue precipitate (Turnbull's blue) | Presence of Fe²⁺ is confirmed |
The given salt contains Fe²⁺ ions as cation and SO₃²⁻ ions as anion. The salt is FeSO₃.