• Oxygen: relights a glowing splint
  • Hydrogen: Pops when a lighted splint is put into a test tube containing hydrogen
  • Carbon Dioxide: Turns limewater cloudy (calcium hydroxide + carbon dioxide --> calcium carbonate + water)
  • Ammonia: Turns damp red litmus paper blue, has a pungent smell, when fumes mixed with those of hydrochloric acid create white smoke
  • Chlorine: Has a characteristic smell; bleaches damp red litmus paper (after turning it blue)