Anions

Question 1

What are anions

Answer 1

Negatively charged ions

Question 2

What are the 3 tests for anions

Answer 2

Carbonate
Sulfate
Halide

Question 3

Describe the test for carbonates

Answer 3

Add dilute HCl to the test sample
Take any gas reduced, run through limewater
Lime water would go cloudy if carbonate was present

Question 4

What is the equation for carbonate + acid

Answer 4

Carbonate + acid —> salt + carbon dioxide + water

Question 5

Describe the test for sulfates

Answer 5

Step 1: add dilute HCl
This removes any carbonate or sulfite ions
Step 2: add barium chloride solution
If sulfate ions are present you’d see them in white precipitate form.

Question 6

Why do we add an acid to remove carbonate or sulfate ions

Answer 6

These ions are impurities as they’d also react to form a precipitate

Question 7

Describe the test for halide ions

Answer 7

Step 1: add dilute nitric acid to remove carbonate and sulfate
Step 2: add silver nitrate
The silver ions will react with the halide ions to form a precipitate

Question 8

What colour precipitate does silver chloride form

Answer 8

White precipitate

Question 9

What colour precipitate does silver bromide form

Answer 9

Cream precipitate

Question 10

What colour precipitate does silver iodide form

Answer 10

Yellow precipitate