Identification of common gases

8.2.1 Test for hydrogen

8.2.2 Test for oxygen

8.2.3 Test for carbon dioxide

8.2.4 Test for chlorine

Gases Test Positive Result
Hydrogen (H2) Burning spit held at the open end of a test tube of gas Burns rapidly with a squeaky pop sound
Oxygen (O2) Insert glowing splint into a test tube of gas Relights
Carbon dioxide (CO2) Bubble through limewater Goes milky or cloudy
Chlorine (Cl2) Damp (blue) litmus (Goes red), then bleaches and turns white
Ammonia (NH3) Damp red litmus Turns blue