4.2.1 tests for gases

• Test for hydrogen - squeaky pop:

  • place a lit splint by the mouth of a test tube containing gas
  • if hydrogen gas is present, a "squeaky pop" noise will be produced
  • noise is made because hydrogen burns quickly in the presence of oxygen to make H2O
• Test for oxygen - glowing splint:

  • insert a glowing splint into a test tube containing a gas
  • if oxygen is present, the glowing splint will relight
• Testing for carbon dioxide - limewater:

  • take an aqueous solution of limewater (calcium hydroxide) and bubble through the gas
  • if the gas is carbon dioxide, the limewater solution will turn from clear to cloudy
• If carbon dioxide is bubbled through limewater, the solution will turn from colourless to cloudy.