Question

There are three constitutional isomers with the molecular formula C5H12. Chlorination of one of these isomers yields only one product. Identify the isomer:

Answer 1

The isomer is 2,2-dimethylpropane

Step-by-step explanation:

The three constitutional isomers of pentane(
`C_(5) H_(12)`) are:

1. n-pentane

2. 2-methylbutane

3. 2,2-dimethylpropane

After chlorination of n-pentane we can get three different products(excluding optical isomers) depending on the position of chlorine atom.

After chlorination of 2-methylbutane we get four different products(excluding optical isomers).

But in the case of 2,2-dimethylpropane we get only one product as all the four carbon atoms attached to a central carbon atom are identical.

This explanation becomes clear after seeing the figure below.