Question

How many constitutional isomers can possibly form during radical chlorination of 2,3-dimethylpentane? Assume that only one chlorine atom is incorporated.

a. 1
b. 2
c. 3
d. 4

Answer 1

There are four possible constitutional isomers for the radical chlorination of 2,3-dimethylpentane because chlorination can occur at one primary carbon (same at both ends of the molecule), two unique secondary carbons, and one tertiary carbon, each yielding a distinct isomer.

Step-by-step explanation:

The question involves determining the number of constitutional isomers that can form during the radical chlorination of 2,3-dimethylpentane when only one chlorine atom is incorporated. To solve this, we need to identify all the unique positions that a chlorine atom can be placed on the carbon backbone of 2,3-dimethylpentane.

Let's consider the structure of 2,3-dimethylpentane. There are three types of carbon atoms:

• Primary carbons - these are carbon atoms bonded to only one other carbon atom. Specifically, in 2,3-dimethylpentane, that would be the end carbons of the pentane chain.
• Secondary carbons - these are carbon atoms bonded to two other carbon atoms. In this molecule, there are two unique secondary carbon atoms we can consider.
• Tertiary carbons - these are carbon atoms bonded to three other carbon atoms. In this molecule, there's only one tertiary carbon atom.

Chlorination at any of these positions would result in a unique isomer. Thus, considering the primary carbons (which are the same either end of the molecule), secondary carbons (two unique ones), and the tertiary carbon, we have a total of four possible constitutional isomers for radical chlorination of 2,3-dimethylpentane.

Therefore, the correct answer is d. 4.