An organic compound reacted with bromine water to give a colourless solution. The compound is probably an?

A. alkene
B. alkanal
C. alkyne
D. alkanone

Correct Answer:

Option A – alkene

Explanation

Alkenes react in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent like tetrachloromethane. The double bond breaks, and a bromine atom becomes attached to each carbon. The bromine loses its original red-brown colour to give a colourless liquid.

Alkynes also react with bromine, decolorising it though not as immediate as alkenes.