Anions Tests

Question 1

Carbonates method

Answer 1

Carbonates react with dilute acids to form carbon dioxide gas. Carbon dioxide can be identified with limewater.

Question 2

Halides method

Answer 2

Halide ions in solution produce precipitates with silver nitrate solution in the presence of dilute nitric acid.

Question 3

Sulphate method

Answer 3

Sulphate ions in solution produce a white precipitate with barium chloride in the presence of dilute hydrochloric acid.

Question 4

Carbonates positive result

Answer 4

Turns limewater cloudy

Question 5

Halides positive result

Answer 5

Produce precipitate
Silver chloride is white.
Silver bromide is cream.
Silver iodide is yellow.

Question 6

Sulphate positive result

Answer 6

White precipitate formed (insoluble barium sulphate)

Question 7

Halides example equations

Answer 7

Sodium chloride + silver nitrate → sliver chloride + sodium chloride
NaCl (aq) + AgNO3 (aq) → AgCl (s) + NaCl (aq)
Sodium bromide + silver nitrate → silver bromide + sodium chloride
NaBr (aq) + AgNO3 (aq) → AgBr (s) + NaCl (aq)
Sodium iodide + silver nitrate → silver iodide + sodium chloride
NaI (aq) + AgNO3 (aq) → AgI (s) + NaCl (aq)

Question 8

Sulphate example equations

Answer 8

Barium chloride + sodium sulfate → barium sulfate + sodium chloride
BaCl2 (aq) + Na2SO4 (aq)→BaSO4 (s) + 2NaCl (aq)