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 |
|---|---|---|
| Confirmatory Test | ||
| Ammonium Molybdate Test Acidify with conc. HNO₃ and add ammonium molybdate solution, boil | Canary yellow precipitate is formed | PO₄³⁻ is confirmed |
| Experiment | Observation | Inference |
|---|---|---|
| Original solution + H₂S gas in presence of NH₄OH | Black precipitate is formed | Group IV cation may be present |
| Dissolve the black sulphide precipitate in aqua regia and heat | Residue remains in solution after evaporation | Co²⁺ may be present |
| Confirmatory Test | ||
| Potassium Hexanitritocobaltate(III) Test Neutralise with NH₄OH, acidify with dilute acetic acid and add strong potassium nitrite solution | Yellow precipitate is formed | Presence of Co²⁺ is confirmed |
The given salt contains Co²⁺ as the cation (basic radical) and PO₄³⁻ as the anion (acidic radical). The salt is Cobalt(II) Phosphate (Co₃(PO₄)₂).