Two hydrocarbons X and Y were treated with bromine water. X decolorised the solution and Y did not not. Which class of compound does Y belong?

A.

Benzene

B.

Alkynes

C.

Alkenes

D.

Alkanes

Correct answer is D

Bromine water is an orange solution of bromine. It becomes colorless when it is shaken with an alkene. Alkenes can decolorize bromine water, but alkanes cannot.

X is ethene which decolorizes bromine water showing that ethene is unsaturated.

Y is an alkane.