Explain the mechanism of the following reactions :
(i) Addition of Grignard reagent to a carbonyl compound forming an adduct followed by hydrolysis.
(ii) Acid catalysed dehydration of alcohol forming an alkene.
(iii) Acid catalysed hydration of an alkene forming an alcohol.

Explanation

The first step of the reaction is the nucleophilic addition of Grignard reagent to the carbonyl group to form an adduct . Hydrolysis of the adduct yields an alcohol.

(ii) The mechnasim of ethanol involves the following steps :
Step 1 : Formation of protonated alcohol

Step 2: Formation of carbocation

Step 3 : Formation of ethene by elimination of a proton

(iii) Acid Catalysed hydration : Alkenes react with water in the presence of acid as catalyst to form alcohols.
Mechanism : The mechanism of the reaction involves the following three steps .