

The test can be performed with bromine water, which is brown in color.
In case of ethene, upon addition of bromine water, the color changes from brown to colorless.
CH2=CH2 + Br2 (brown) → BrCH2-CH2Br (colorless)
In case of ethane, bromine water does not react as there is no unsaturated double bond, and color remains brown.
