Background:

Chlorine: A greenish-yellow gas at room temperature

Bromine: A reddish brown liquid at room temperature

Iodine: Usually found in its salts (iodides)

Methods:

Test for chloride

Place a small amount of sodium chloride, dilute nitric acid and a few drops of silver nitrate solution in a test tube.

White precipitate will form.

Precipitate turns darker in sunlight and dissolves when a dilute solution of ammonia is added.

Test for bromide:

Place a small amount of sodium bromide, dilute nitric acid and a few drops of sliver nitrate in a test tube.

Pale yellow precipitate will form.

Precipitate does not dissolve in dilute ammonia solution, but does dissolve in concentrated ammonia solution.

Test for iodide:

Place a small amount of sodium iodide, dilute nitric acid and a few drops of sliver nitrate in a test tube.

Yellow precipitate will form.

Precipitate is insoluble in ammonia solution.

Chemical equations:

Ag+(aq)+X−(aq)−>AgXl(s

where X is the halide anion