How many monochlorination products can be formed (constitutional isomers only) from the reaction of (CH3)2CHCH2CH3 with Cl2 and hν?

4 monochlorination products can be formed.

Explanation:

Constitutional isomers : These are those compounds with same molecular formula but different atomic arrangement.For example: butane and 2-methly-propane.

On monochlorination of 2 methyl-butane  we will have four possibilities of product which will be constitutional isomers of each other:

a