Question

The IUPAC name of the given compound is

• A. 4- Ethyl 5- Methylhexane
• B. 3- Ethyl 2- Methylhexane
• C. 2- Methyl 3- Ethylhexane
• D. 5- Methyl 4- Ethylhexane

Answer 1

The correct option is B

3- Ethyl 2- Methylhexane

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 6 carbons long.

If more than one branch is present, as per rule, numbering should be done either from left to right or right to left so as to get the lowest number for the branch coming first in the longest chain. One methyl substituent is at carbon number 2 and one ethyl substituent is at carbon number 3. If different radicals are present as branches then the name of the branches should be written in alphabetical order. Hence, the name is 3- Ethyl 2- Methylhexane.