Question

identify the name of the carboxylic acid shown below.
select the correct answer below:
4 - isopropylpentanoic acid
2 - ethyl - 3 - methylbutanoic acid
2 - isopropylpentanoic acid

Explanation:

Step1: Determine the parent chain

The longest carbon chain containing the carboxyl group ($-COOH$) is 5 - carbon long (pentanoic acid).

Step2: Identify substituents

There is an isopropyl ($-CH(CH_3)_2$) group attached to the second carbon atom of the parent chain.

Step3: Name the compound

According to IUPAC naming rules for carboxylic acids, we name it as 2 - isopropylpentanoic acid.

For 4 - isopropylpentanoic acid: The isopropyl group is not on the 4th carbon of the correct parent chain.
For 2 - ethyl - 3 - methylbutanoic acid: The parent chain is not the longest possible chain that includes the carboxyl group.

Answer:

2 - isopropylpentanoic acid