Tests for Ions
Year 10 (IGCSE) 🧪 Acids, Bases & Salts Apply flame tests and precipitate tests to identify metal and non-metal ions.
🔬 Flame Tests
| Ion | Flame colour |
|---|---|
| Li⁺ | Crimson/red |
| Na⁺ | Golden yellow |
| K⁺ | Lilac/violet |
| Ca²⁺ | Brick red/orange-red |
| Ba²⁺ | Green |
| Cu²⁺ | Blue-green |
Use blue cobalt glass filter to see K⁺ (lilac) — it blocks yellow Na⁺ flame.
🧪 NaOH Precipitate Tests
| Ion | Precipitate colour | Dissolves in excess NaOH? |
|---|---|---|
| Cu²⁺ | Blue | No |
| Fe²⁺ | Green | No |
| Fe³⁺ | Red-brown | No |
| Al³⁺ | White | Yes (amphoteric) |
🧪 Anion Tests
| Anion | Test | Positive result |
|---|---|---|
| Cl⁻, Br⁻, I⁻ | AgNO₃ + dilute HNO₃ | White/cream/yellow ppt |
| SO₄²⁻ | BaCl₂ + dilute HCl | White BaSO₄ ppt |
| CO₃²⁻ | Dilute HCl; test gas | CO₂ turns limewater milky |
Ready to test yourself? Click the Quiz tab above to practise questions on this topic!
Interactive Demonstration — Tests for Ions
Select an ion to see its confirmatory test and expected observation.
Select an ion above to see its test.
🔬 Ion Test Identifier
Calculate moles of precipitate formed in ionic tests.