Saturation Test (Edexcel International A Level Chemistry)

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