Test for positive and negative ions
A mind map to show the different ways to test for negative and positive ions, gcse higher tier chemistry AQA
- Created by: Asha
- Created on: 31-03-13 14:29
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- Test for ions
- POSITIVE IONS
- Flame test
- Lithium(Li+) - Crimson ( red)
- Sodium(Na+) - yellow
- Potassium (K+) - Lilac
- Calcium ( Ca2+) - Red
- Lithium(Li+) - Crimson ( red)
- Barium (Ba2+)- green
- Sodium Hydroxide
- When sodium hydroxide Is added to solutions of ions with 2+ and 3+ a precipitate of the metal hydroxide forms
- Aluminium, calcium and magnesium ions form white precipitates
- Copper(II) hydroxide is blue
- Iron(II) hydroxide is green
- Iron(III) hydroxide is brown
- Flame test
- NEGATIVE IONS
- Carbonate ions: add dilute hydrochloric acid to the substance to see if it fizzes.
- If it does and the gas produced turns limewater milky, it contains carbonate ions
- Halide ions: Add dilute nitric acid and silver nitrate solution
- Chloride ions give a white precipitate
- Bromide ions give a cream precipitate
- Iodide ions give a yellow precipitate
- Sulfate ions: Add dilute hydrochloric acid and then barium chloride solution
- If a white precipitate forms, sulphate ions are present
- Carbonate ions: add dilute hydrochloric acid to the substance to see if it fizzes.
- POSITIVE IONS
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