Question

Based on the table given below, why there is a difference in these observations??

Answer 1

Propene is unsaturated.

Explanation:

Propane is a saturated hydrocarbon meaning it has all single bonds. Propene is unsaturated and has one carbon to carbon double bond. This is a reactive centre and can undergo electrophilic addition reaction. It does so with `Br_2` to form 1,2-dibromopropane, which is saturated and decolourises bromine.

The reaction with bromine is a standard test for distinguishing between a saturated alkane and an unsaturated Alkene.