Conduct qualitative investigations to test for the presence in organic molecules

Detection of carbon-carbon double bonds

  • In a test tube, a sample is taken.
  • Bromine water, which is yellow in colour is added to the sample. The bromine water, if turns colourless will confirm the presence of carbon-carbon double bonds i.e. alkenes.

Detection of hydroxyl groups

  • Hydroxyl groups in organic compounds can be tested by the Iodoform test.
  • If a sample, when heated with sodium hydroxide and iodine turns colourless from yellow, it reflects the presence of hydroxyl group.

Detection of carboxylic acids

  • For detection of carboxylic acids, sodium hydrogen carbonate is added with a taken sample. If a brisk effervescence is observed, it indicates the presence of carboxylic acid because carboxylic acids react with sodium bicarbonate to produce carbon dioxide which results in the formation of the effervescence.