91Ó°ÊÓ

In halogenation, alkanes react with halogens to form alkyl halides in the presence of light or heat, also known as radical substitution reaction.Halogenation involves radical intermediates.

The general reaction scheme is shown below:

Radical substitution Rreaction

Chlorine and bromine are the two most common reagents for radical substitution reaction, but they react differently. Chlorine is unselective in nature and reacts to form a mixture of products, whereas bromine reacts to selectively give the major product.

a.

When the given compound reacts with chlorine in the presence of light, the mixture of products that are formed are given below:

Chlorination of compound a.

b.

Since bromine is selective in nature, it gives the two possible major products, as shown below

Bromination of compound b.

c.

Similarly, the two major products are given below:

Bromination in compound c.

d.

Chlorination in compound d.