Question

Which of the following gives benzoic acid on oxidation
A. Chlorophenol
B. Chlorotoluene
C. Chlorobenzene
D. Benzyl chloride

Answer 1

Hint: Oxidation is the addition of oxygen to a compound. It involves the loss of electrons increasing the oxidation state of a compound.

Complete Step by Step Solution:
Benzoic acid is an organic compound.
It is the simplest aromatic carboxylic acid.
It exists typically in many plants and is used as an intermediate in the biological synthesis of many secondary metabolites.

A. Chlorophenol
The chemical formula of chlorophenol is \[{{\rm{C}}_{\rm{6}}}{{\rm{H}}_{\rm{4}}}{\rm{OH}}\left( {{\rm{Cl}}} \right)\].
In this, there is a chlorine group attached to the ortho position of phenol.
The oxidation of this compound will give a combination of benzene diol compounds.
The reaction will occur as follows:

Image: Oxidation of chlorophenol.
It will not give benzoic acid as a product.
So, A is incorrect.

B. Chlorotoluene
The chemical formula of chlorotoluene is \[{{\rm{C}}_{\rm{6}}}{{\rm{H}}_{\rm{4}}}{\rm{C}}{{\rm{H}}_3}{\rm{(Cl)}}\].
In this, there is a chlorine group attached to the ortho position of toluene.
The oxidation of this compound will give chlorobenzoic acid.
The reaction will occur as follows:

Image: Oxidation of chlorotoluene.
It will not give benzoic acid as a product.
So, B is incorrect.

C. Chlorobenzene
The chemical formula of chlorobenzene is \[{{\rm{C}}_{\rm{6}}}{{\rm{H}}_5}{\rm{Cl}}\].
In this, there is a chlorine group attached to the benzene.
The oxidation of this compound will not give benzoic acid.
So, C is incorrect.

D. Benzyl chloride
The chemical formula of benzyl chloride is \[{{\rm{C}}_{\rm{6}}}{{\rm{H}}_5}{\rm{C}}{{\rm{H}}_{\rm{2}}}{\rm{Cl}}\].
The oxidation of this compound will give benzoic acid.
The oxidation of this compound can be in the presence of alkaline potassium permanganate or potassium dichromate.
The reaction will occur as follows:

Image: Oxidation of benzyl chloride.
It will give benzoic acid as a product.
So, D is incorrect.

So, option D is correct.

Note: While attempting the question, one must know about the structures of every given option. The oxidation of benzyl chloride out of the given options will yield benzoic acid. Oxidation of chlorophenol, chlorotoluene, and chlorobenzene will yield benzene diols, chlorobenzoic acid, and ortho-substituted oxy-chlorobenzene respectively.