JEE Advanced Chemistry: Organic Chemistry: Functional Groups (Esters) questions with solutions

Q1. Identify the correct IUPAC common name for the ester: CH3-CH(CH3)-C(=O)-O-C(CH3)3

1. Neo butyl isobutyrate
2. t-Butyl n-butyrate
3. t-Butyl isobutyrate
4. Iso butyl isobutyrate

Answer: t-Butyl isobutyrate

The carbonyl-side fragment CH3CH(CH3)CO- is isobutyryl (from isobutyric acid, a branched C4 acid). The oxygen-side fragment -OC(CH3)3 is tert-butoxy (from tert-butanol). The ester is therefore tert-butyl isobutyrate.