Tests for Anions

Question 1

How do you test for carbonates in a solution?

Answer 1

Put the sample in a test tube, add dilute acid. Connect the test tube to a test tube of lime water. If carbon dioxide is present then the lime water will turn cloudy.

Question 2

How do you test for sulfates in a solution, give the half equation?

Answer 2

Add drops of dilute hydrochloric acid with a couple drops of barium chloride to the mystery solution. If sulfates are present then a white precipitate will form.

Ba2+ + SO42- —-> BaSO4

Question 3

Why is hydrochloric acid added when testing for sulfates?

Answer 3

To get rid of carbonate ions. These would also produce a white precipitate so they’d give a false positive result.

Question 4

What are most carbonates insoluble in?

Answer 4

Water, except for group 1 carbonates

Question 5

How do you test for halides?

Answer 5

Add drops of dilute nitric acid with a couple drops of silver nitrate solution to the mystery solution.

Chloride - White precipitate
Bromide - Cream precipitate
Iodide - Yellow precipitate