C21 Gas Tests

Question 1

Test for hydrogen

Answer 1

A lighted wooden splint makes a popping sound in a test tube of hydrogen.

Question 2

Oxygen

Answer 2

A glowing wooden splint relights in a test tube of oxygen.

Question 3

Carbon dioxide

Answer 3

Carbon dioxide turns limewater milky. A lighted wooden splint goes out in a test tube of carbon dioxide but this happens with other gases, too. So the limewater test is a better choice.

Question 4

Ammonia

Answer 4

Ammonia has a characteristic sharp, choking smell. It also makes damp red litmus paper turn blue. Ammonia forms a white smoke of ammonium chloride when hydrogen chloride gas, from concentrated hydrochloric acid, is held near it.

Question 5

Chlorine

Answer 5

Chlorine has a characteristic sharp, choking smell. It also makes damp blue litmus paper turn red, and then bleaches it white. Chlorine makes damp starch-iodide paper turn blue-black.