Here are the tests used to identify anions.
anion | test | Positive test results |
carbonate, CO₃²⁻ | Add dilute acid, then test for carbon dioxide gas. | Effervescence of carbon dioxide gas is produced. |
chloride, Cl⁻(must be in solution) | Acidify with dilute nitric acid, then add aqueous silver nitrate. | White ppt. |
bromide, Br⁻(must be in solution) | Acidify with dilute nitric acid, then add aqueous silver nitrate. | Cream ppt. |
Iodide, I⁻(must be in solution) | Acidify with dilute nitric acid, then add aqueous silver nitrate. | Yellow ppt. |
nitrate, NO₃⁻(must be in solution) | Add aqueous sodium hydroxide, then aluminium foil, then warm carefully. | Ammonia gas is produced. |
sulfate, SO₄²⁻(must be in solution) | Acidify with dilute nitric acid, then add aqueous barium nitrate. | White ppt. |
sulfite, SO₃²⁻ | Add a small volume of acidified aqueous potassium manganate (VII) | Purple acidified aqueous potassium manganate (VII) turns colourless. |
Watch this video here on how to test for these anions: carbonate, chloride, iodide, nitrate and sulfate:
This video here shows the difference in test results for chloride, bromide and iodide anions:
Watch this video for the test for sulfite ions: