Tests for common gases

• Test for hydrogen


  1. Use a burning splint held at the open end of a test tube of the gas

  2. Creates a 'squeaky pop' sound (hydrogen burns rapidly)
• Test for oxygen


  1. Uses a glowing splint inserted into a test tube of the gas

  2. Splint relights in oxygen
• Test for carbon dioxide

  1. Bubble the gas through the limewater (calcium hydroxide (aq))

  2. It will turn milky (cloudy)
• Test for chlorine


  1. Use damp litmus paper

  2. When damp litmus paper is put into chlorine gas the litmus paper is bleached and turns white
• Carbon dioxide reacts with limewater to form calcium hydrogen carbonate, which turns milky white.
• If there are bubbles present, it indicates that the gas being tested was not pure CO2 but contained oxygen or nitrogen as well.