Chemical tests

Stage 1

Identify the unknown gas, anion or cation in the following tests.

1. Give the name and formula (including charge) of the ion that gives a lilac flame.

2. Give the name and formula (including charge) of the ion that gives a cream precipitate when acidified silver nitrate is added.

3. Give the name and formula (including charge) of the ion that fizzes and gives off carbon dioxide when a dilute acid is added.

4. Give the name and formula (including charge) of the ion that gives a white precipitate when acidified barium chloride is added.

5. Give the name and formula (including charge) of the ion that gives a green precipitate when sodium hydroxide solution is added.

Stage 2

6. Identify the unknown compound from the following chemical tests:

  • A white precipitate was produced when aqueous sodium hydroxide was added, and redissolved with excess.
  • Gave a cream precipitate when acidified silver nitrate was added.

7. Identify the unknown compound from the following chemical tests:

  • A flame test gave a green flame.
  • Gave a white precipitate when acidified barium chloride was added.

8. Identify the unknown compound from the following chemical tests:

  • A white precipitate was produced when aqueous sodium hydroxide was added, and redissolved with excess.
  • Gave a yellow precipitate when acidified silver nitrate was added.

9. Identify the unknown compound from the following chemical tests:

  • A flame test gave a orange-red flame.
  • Fizzed and gave off a gas when a dilute acid was added. The gas turned limewater cloudy.

10. Identify the unknown compound from the following chemical tests:

  • A brown precipitate was produced when aqueous sodium hydroxide was added.
  • Gave a white precipitate when acidified silver nitrate was added.

Stage 1

1. potassium, K+

2. bromide, Br-

3. carbonate, CO32-

4. sulfate, SO42-

5. iron(II), Fe2+

Stage 2

6. aluminium(III)bromide

7. copper(II)sulfate

8. aluminium(III)iodide

9. calcium(II)carbonate

10. iron(III)chloride