Ion Tests

Question 1

Correct order of tests

Answer 1

Carbonates

Sulfates

Halides

Question 2

To test for carbonates

Answer 2

Add dilute acid

Gas produced

Gas turns limewater cloudy

Question 3

Test for sulfates

Answer 3

Add dilute HCl and then barium chloride solution

White precipitate= barium sulfate

Question 4

Test for halides ( 2 step )

Answer 4

Add nitric acid then silver nitrate solution

Chloride=white=dissolves in dilute NH3
Bromide=cream=dissolves in conc NH3
Iodide=yellow=insoluble in con NH3

Question 5

Test for ammonia

Answer 5

Use damp red litmus paper

Will turn blue

Question 6

Test for ammonium

Answer 6

Add sodium hydroxide

Then do ammonia test

Damp red litmus paper turns blue

Question 7

False positives

Answer 7

Barium carbonate and barium Sulfite also produce a white precipitate

Sulfate ions also precipitate with silver nitrate

Question 8

Removing false positive (2)

Answer 8

Do it in correct order

Add a dilute acid which won’t interfere with the results