Write the mechanism of aicd catalysed dehydration of ethanol to ethane.

Explanation

(a) Mechanism involves three steps
Steps 1. Formation of protonated alcohol :
Alcohols react with sulphuric acid to form protonated alcohol.

Step - 2 : Formation of Carbocation :
The protonated alcohol loses a molecule of water to form ethyl carbocation.

Step 3 : Formation of ethene by elimination of a proton :
The carbocation loses a proton to form ethene.

(b) Anisole undergoes Friedal crafts reactions with methyl chloride in presence of anhydrous aluminium chloride. Methyl groups are introduced at ortho and para positions.