(h) Chemical tests

Describe tests for these gases:

• hydrogen
• oxygen
• carbon dioxide
• ammonia
• chlorine.

Describe how to carry out a flame test

Know the colours formed in flame tests for these cations:

• Li+ is red
• Na+ is yellow
• K+ is lilac
• Ca2+ is orange-red
• Cu2+ is blue-green.

Describe tests for these cations:

• NH4+ using sodium hydroxide solution and identifying the gas evolved
• Cu2+, Fe2+ and Fe3+ using sodium hydroxide solution.

Describe tests for Cl⁻, Br⁻ and I⁻ using acidified silver nitrate; SO₄²⁻ using acidified barium chloride; and CO₃²⁻ using hydrochloric acid and identification of the evolved gas.

Describe a test for the presence of water using anhydrous copper(II) sulfate

Describe a physical test to show whether a sample of water is pure