Tests for anions

Carbonate test

1) In a test tube, add dilute nitric acid to the solid or solution to be tested

2) If you see bubbles, the unknown compound could be a carbonate

3)Bubble the gas through limewater, carbon dioxide to form a fine white precipitate of calcium carbonate, which turns the limewater cloudy

Sulfate test

Add Ba2+ ions in the form of BaCl or BaNO3, the Ba+2 ions will react with the sulfate ions to form BaSO4

Which order should you carry out the tests in?

Carbonate test should be first, because if you carry out a sulfate test on a carbonate, it will form a white precipitate just like a sulfate ion will. Halide test should be last as AgCO3 and Ag2SO4 are both insoluble in water and will form precipitates

Test for ammonium ions

NaOH is added to a solution, ammonia gas is produced, unlikely to see bubbles as ammonia is very soluble in water. Mixture is warmed and ammonia gas is released. Test the gas with moist pH paper, ammonia will turn it blue