Test for Gases

• Chlorine test:

  • Test tube with substance you think has chlorine
  • Dampen blue litmus paper and put in test tube
  • If it goes from blue to white chlorine is present
  • If paper briefly turns red it is due to chlorine forming HCl on the paper
  • Chlorine is poisonous, so in experiment wear mask or go in a fume cupboard
• Oxygen test:

  • Use a glowing splint (no flame)
  • Put in gas test tube
  • If oxygen is present gas will relight
• Hydrogen test:

  • Lit splint
  • Place in test tube with gas
  • If hydrogen is present we will hear a squeaky pop
• Carbon dioxide test:

  • Put gas in one test tube and link it through a sealed tube to an aqueous solution of limewater (calcium hydroxide)
  • bubble gas into limewater
  • limewater will go cloudy as when COz and Ca(OH)2 react it forms calcium carbonate.
  • Calcium carbonate is a solid which makes it cloudy.