Anions

Carbonates

Add HCl to substance and test for Carbon Dioxide.

Sulphates

Add HCl and Barium Chloride to form a white precipitate.

Halides

Halide	Colour
Chloride (Cl-)	White
Bromide (Br-)	Cream

Iodide (I-)	Yellow

Tests for Halides Method (Cl^-, Br^-, I^-)

1. Add 1cm³ of each halide solution to 3 different test tubes.

2. Add 5 drops of HIVO₃ (to remove any CO₃^2- ions which would also form a precipitate.

3. Add silver nitrate in drops

4. Observe the colour of the precipitate formed.

Test for Carbonate ions method: (CO₃^2-)

1. Add 1 spatula of metal carbonate to a test tube/boiling tube

2. Add 3cm³ of limewater to a different test tube/boiling tube

3. Add HCl to the metal carbonate and quickly connect the delivery tube to the top of the test tube/boiling tube and place the glass tube in the limewater.

Result: If limewater turns cloudy then CO₂ was given off and there were CO₃^2- ions present in the original sample.

Test for sulate ions method: (SO₄^2-)

1. Add 1cm³ of an ‘unknown’ solution, which may contain sulfate ions, to a test tube.

2. Add 5 drops of HCl (this removes any CO₃^2- ions which would give a false positive)

3. Add 3 drops of Barium Chloride solution

Result: If a white precipitate (BaSO₄) form the SO₄^2- ion were present.