Testing for Anions

Question 1

Testing for Carbonates

Answer 1

• react carbonate with an acid
• this should produce a salt, carbon dioxide and water
• bubble carbon dioxide gas through limewater and the limewater should turn cloudy

Question 2

Testing for Sulfates

Answer 2

• barium ions react with sulphate ions to produce barium sulphate, which shows a white precipitate
• add dilute hydrochloric acid to remove impurities, carbonate/sulphite ions that could react with barium ions
• add barium chloride solution
• sulphate ions displace chloride ions and form barium sulphate

Question 3

Testing Halide Ions

Answer 3

• add dilute nitric acid to remove any impurities, carbonate/sulphite ions that may react with silver
• add silver nitrate solution
• silver halide compound forms a coloured precipitate

Question 4

Chloride Ion Precipitate

Answer 4

white precipitate
- silver chloride

Question 5

Bromide Ion Precipitate

Answer 5

cream precipitate
- silver bromide

Question 6

Iodide Ion Precipitate

Answer 6

yellow precipitate
- silver iodide