ASChemistryCIERevision Notes14. Hydrocarbons14.2 AlkenesTest for Unsaturation

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Test for Unsaturation (CIE AS Chemistry)

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Test for Unsaturation

  • Halogens can be used to test if a molecule is unsaturated (i.e. contains a double bond)
  • Br2 (aq) is an orange or yellow solution, called bromine water and this is the halogen most commonly used
  • The unknown compound is shaken with the bromine water
  • If the compound is unsaturated, an addition reaction will take place and the coloured solution will decolourise

The unsaturation test

Hydrocarbons Bromine Water, downloadable AS & A Level Chemistry revision notes

The decolourisation of bromine water by an unsaturated compound as a result of an addition reaction

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    Philippa

    Author: Philippa

    Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener.