Question

Question: Explain why radical bromination of p-xylene forms C rather than D.

Short answer

Answer

The radical bromination of xylene gives p-benzyl bromo toluene (C) rather than (D) because the weakest C-H bond is cleaved with the lowest bond dissociation enthalpy.

Step-by-step solution

Xylene

An aromatic hydrocarbon in which two methyl groups are on adjacent carbon atoms is known as xylene or dimethylbenzene.

Radical bromination

The radical bromination of xylene gives p-benzyl bromo toluene because of the following reasons:

a) The C-H bond of the benzyl ring is stronger due to hybridized carbon than the C-H bond of the methyl group with hybridized carbon atom. The weakest C-H bond is cleaved during bromination giving C rather than D.

b) The bond with the lowest bond dissociation enthalpy is cleaved to form the bromination product.