Bromine water is an orange solution of bromine. It becomes colourless when it is shaken with an alkene. Alkenes can decolourise bromine water, but alkanes cannot. The slideshow shows this process.

The rapid disappearance of the amber color of the bromine at room temperature is characteristic of reaction with alkenes ... To Conduct Demonstration: Pour two samples of heptane and two samples of ...

Hydrocarbons – because they contain hydrogen and carbon only. Unsaturated – because they contain at least one C=C. Each alkene containing one C=C has two fewer hydrogen atoms than the ...