Question

From the given diagram, find the IUPAC name of the compound.

• A. 3 - Methylbutane
• B. 2 - Ethylpropane
• C. 2 - Methylbutane
• D. Methylbutane

Answer 1

The correct option is C

2 - Methylbutane

Let us begin by numbering the longest chain. According to the IUPAC rules of nomenclature the longest chain should be considered as the main chain. No matter which outer carbon we start with, the longest chain is 4 carbons long.

The numbering should be done either from left to right or right to left so as to get the lowest number for the branch. When we start numbering from left to right then the methyl substituent is present at the 2nd carbon. Therefore, the IUPAC name of the compound is 2 - methyl butane.