CIE AS Chemistry (9701) exams from 2022

Revision Notes

3.2.9 Test for Unsaturation

Test for Unsaturation

  • Halogens can be used to test if a molecule is unsaturated (i.e. contain a double bond)
  • Cl2 is a very pale green solution, called chlorine water
  • Br2 is an orange or yellow solution, called bromine water
  • The unknown compound is shaken with the chlorine/bromine water
  • If the compound is unsaturated, an addition reaction will take place and the coloured solutions will decolourise over time

 

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

 

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

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

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Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.
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