Qualitative Anaylsis

Question 1

How are ammonium ions tested for?

Answer 1

• Add a small volume of dilute NaOH (aq) and warm gently.
• Collect gas produced and test with damp red litmus paper.
• Should turn blue in presence of ammonia gas.

Question 2

How are carbonate ions tested for?

Answer 2

• Add a small amount of dilute acid.
• Reaction should effervesce.
• Gas produced can be collected and bubbled through limewater.

Question 3

How are sulfate ions tested for?

Answer 3

• Add a small amount of Ba(NO3)2.
• White precipitate should form due to BaSO4 formation.

Question 4

How are chloride ions tested for?

Answer 4

• First add HNO3 to remove any carbonate ions.
• Add a small amount of AgNO3 (aq)
• A white precipitate should form.
• The precipitate will dissolve in dilute ammonia solution.

Question 5

How are bromide ions tested for?

Answer 5

• First add HNO3 to remove any carbonate ions.
• Add a small amount of AgNO3 (aq)
• A cream precipitate should form.
• The precipitate will dissolve in concentrated ammonia solution.

Question 6

How are iodide ions tested for?

Answer 6

• First add HNO3 to remove any carbonate ions.
• Add a small amount of AgNO3 (aq)
• A yellow precipitate should form.
• The precipitate will not dissolve in conc. ammonia solution.

Question 7

What is the correct order for anion tests?

Answer 7

• Carbonate, Sulfate, Halide.
  CASH