There are 9 different isomers of C7H16. Name the 1 isomer of C7H16 that contains an ethyl branch on the parent chain

3-ethylpentane.

Explanation:

Hello,

In this case, considering that an ethyl radical is required at the main chain the place at which it is considered a radical is at the third carbon of a pentane, which is named as 3-ethylpentane taking into account the attached picture. It is important to notice that if such ethyl was at a different carbon atom, name will be 3-methyl-hexane which is not as required.

Regards.

it is the most commonly accepted one