Qualitative analysis
How to do salt analysis · Viva · Quiz
To analyse the given inorganic salt for one acidic and one basic radical.
| Experiment | Observation | Inference |
|---|---|---|
| Warm the salt with dilute H₂SO₄ | Colourless gas with smell of rotten eggs is evolved | S²⁻ may be present |
| Confirmatory Tests | ||
| Lead Acetate Test Pass gas through filter paper dipped in lead acetate solution | Paper turns black | S²⁻ is confirmed |
| Sodium Nitroprusside Test Make solution alkaline with NH₄OH (or sodium carbonate extract) and add sodium nitroprusside solution | Purple/violet colouration is produced | S²⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + Dilute HCl | No reaction | Group I cation is absent |
| Original solution + Dilute HCl + H₂S gas (with NH₄Cl) | No reaction | Group II cation is absent |
| Original solution + Dilute HCl + NH₄Cl solid + NH₄OH | No reaction | Group III cation is absent |
| Original solution + NH₄Cl + NH₄OH + (NH₄)₂CO₃ | White ppt is formed | Group V cation may be present |
| Confirmatory Tests | ||
| Flame Test Moisten the salt with conc. HCl and introduce it into a non-luminous flame on a platinum / nichrome wire | Apple-green flame | Ba²⁺ is confirmed |
| Potassium Chromate Test Dissolve the white precipitate in dilute acetic acid and add potassium chromate | Yellow precipitate of barium chromate | Ba²⁺ is confirmed |
The given salt contains Ba²⁺ as the cation (basic radical) and S²⁻ as the anion (acidic radical). The salt is Barium Sulphide (BaS).