Question

Of the five isomers of hexanes, the isomer which can give two monochlorinated compounds is:

A.2-methyl pentane
B.2,2-dimethylbutane
C.2,3-dimethylbutane
D.n-hexane

Answer 1

Hint: We know that isomers are the compounds which possess the same molecular formula but different atomic arrangement. There are different types of isomers namely, functional isomers, tautomers, constitutional isomers etc.

Complete step by step answer:
Let us first draw all the isomers of ${{\rm{C}}_{\rm{6}}}{{\rm{H}}_{{\rm{14}}}}$.

1.

2.

3.

4 .

5 .

Let us understand the condition of formation of two monochlorinated products. If the isomeric hexane has two different types of hydrogen and four similar types of hydrogen, then it undergoes reaction with chlorine in presence of light to give two monochlorinated products.

Now, we have to identify the isomer of hexane possessing two different types of H and 4 similar types of H.

In 2,3-dimethyl butane, 2 types of hydrogen are present.

From the above structure, it is clear that there are two different types of hydrogen (a and b) and four similar types hydrogen (a). So, two positions are available for chlorination. Hence,2,3-dimethylbutane gives two monochlorinated products.

The monochlorination reaction is shown as below:

So, out of five isomers of hexane 2,3-dimethylbutane gives monochlorinated products.

So, the correct answer is Option C .

Note: Always remember that the type of hydrogens in a compound decides the number of monochlorinated products. For example, methane has only one type of hydrogen. So, it gives only one monochlorination product, that is,

Pentane is the compound in which three types of hydrogen present. So, it will give three monochlorination products.