Question

The common and IUPAC names for the group, (CH₃)₂CHCH₂ respectively are ______.

Options

• Isobutyl, 2-methylpropyl

• Isobutyl, 1-methylpropyl

• tert-Butyl, 1, 1-dimethyethyl

• Sec-Butyl, 2-methylpropyl

Answer 1

The common and IUPAC names for the group, (CH₃)₂CHCH₂ respectively are Isobutyl, 2-methylpropyl.

Explanation:

The branched \(4\text{-carbon}\) alkyl chain with a methyl group on the second-to-last carbon is commonly called isobutyl. In IUPAC, numbering starts from the attached carbon: \(-\overset{1}{\text{C}}\text{H}_2-\overset{2}{\text{CH}}(\text{CH}_3)-\overset{3}{\text{CH}}_3\), which makes it 2-methylpropyl.