Chemical Tests

Question 1

Test for chloride ions, bromide ions and iodide ions

Answer 1

1. Add nitric acid to remove any impurities
2. Then add silver nitrate solution (AgNO3)

• if chloride ions are present then a white precipitate of silver chloride will form ]
• if bromide ions are present then a cream precipitate of silver bromide will form
• if iodide ions are present then a yellow precipitate of silver iodide will form

Question 2

Test for sulfate ions

Answer 2

1. Add hydrochloric acid to remove any impurities in the solution e.g. carbonate ions
2. Then add barium chloride solution

• if sulfate ions are present then a white precipitate of barium sulfate will form

Question 3

Test for carbonate ions

Answer 3

1. Add hydrochloric acid To solution

• if carbonate ions are present then fizzing will occur.
• test the gas for carbon dioxide by bubbling it through limewater.

Question 4

Test for ammonium

Answer 4

• add sodium hydroxide to solution
• gently warm solution to react both liquids together
• if ammonium was present. In original solution then ammonia gas will be formed
• we can test for this by using red litmus player and if it turns blue then ammonia gas is present.

Question 5

Test for Cu2+, Fe2+ and Fe3+

Answer 5

• add sodium hydroxide to solution that could contain any of these ions.
• if copper (II) ions are present then a blue precipitate of copper hydroxide will form.
• If iron (II) ions are present then a green precipitate of iron(II) hydroxide will form
  If iron(III) ions are present then a brown precipitate of iron (III) hydroxide will be present.

Question 6

Test for the presence of water using anhydrous copper

Answer 6

Add anhydrous copper (II) sulfate to a sample

• if water is present then the anhydrous copper sulfate will turn from white to blue