4.8.2 Identification of common gases

Question 1

How is hydrogen tested?

Answer 1

The test for hydrogen uses a burning splint held at the open end of a test tube of the gas. Hydrogen burns rapidly with a pop sound.

Question 2

How is oxygen tested?

Answer 2

The test for oxygen uses a glowing splint inserted into a test tube of the gas. The splint relights in oxygen.

Question 3

How is carbon dioxide tested?

Answer 3

The test for carbon dioxide uses an aqueous solution of calcium hydroxide (lime water). When carbon dioxide is shaken with or bubbled through limewater, the limewater turns milky (cloudy).

Question 4

How is chlorine tested?

Answer 4

The test for chlorine uses litmus paper. When damp litmus paper is put into chlorine gas, the litmus paper is bleached and turns white.