To determine the presence of anion and cation in the given salt
| Experiment | Observation | Inference |
|---|---|---|
| Take the salt and treat with concentrated H₂SO₄ | Colourless gas evolves and it etches glass | F⁻ may be present |
| Confirmatory Test | ||
| Calcium Chloride Test Treat salt solution with calcium chloride solution | White gelatinous precipitate forms | Presence of F⁻ 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 F⁻ ions as anion. The salt is Fe(F)₃.