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