Chapter 25.5, Problem 1PPB

Interpretation Introduction

Interpretation:

The possible products formed in the electrophilic substitution of chlorobenzene with bisulfite ion are to be shown.

Concept introduction:

Substitution reaction involves the replacement of a group by another group of the same type.

Substitution reactions are of two types, electrophilic substitution, in which an electrophile substitutes another electrophile, and nucleophilic substitution, in which a nucleophile substitutes another nucleophile.

The replacement of a proton by electrophile in aromatic compounds is an example of electrophilic substitution reaction. It involves the addition of electrophile on one of the pi bonds of aromatic system followed by the resonance stabilization of the generated carbocation. Then, in the last step, the proton gets eliminated and the pi bonded system is restored.

If the aromatic ring is already substituted, then the incoming group gets attached at either ortho (position adjacent to already existing group), meta (position next to adjacent of already existing group) or para (position opposite to already existing group) positions depending on the nature of both the groups.