Explain the mechanism of acid catalysed hydration of an alkene to form corresponding alcohol.

To explain this acid catalysed hydration of alkene, we take an alkene like butene and see how the formation of 2° alcohol takes place instead of 1° .

Addition of water in acidic medium to but-1-ene yields butan-2-ol and not butan-1-ol. This is due to the formation of more stable intermediate 2° carbocation instead of the less stable 1° carbocation as the reaction proceeds in normal acidic condition. This is because it follows Markovnikoff’s Rule of addition.

According to it, it can be deduced that the hydroxyl group (from water) adds to the carbon of alkene having fewer number of hydrogen substituents and the hydrogen ion (from water) adds to the carbon of the alkene with more hydrogen substituents. Thus the formation of butan-2-ol is preferred.

This is the step by step explanation about the formation of butan-2-ol.