Chapter 21, Problem 15STP

Interpretation Introduction

Interpretation:

The name of compound should be determined for the following skeletal structure.

1. 2, 2, 3-trimethyl-3-ethylpentane
2. 3-ethyl-3, 4, 4-trimethylpentane
3. 2-butyl-2-ethylbutane
4. is 3-ethyl-2, 2, 3-trimethylpentane
5. 2, 2-dimethyl, 3-diethyl, 3-methylpropane

Concept introduction:

Compounds consist of carbon and hydrogen is known as hydrocarbons. Saturated hydrocarbon is known as alkane having general molecular formula ${\text{C}}_n{\text{H}}_{2n+2}$.

Rules of naming alkanes are:

1. First choose the longest continuous chain of carbon atoms known as parent chain and determines the base name of alkane.
2. The numbering of parent chain should be done in a way that the substituents get the lowest number.
3. The appropriate name should be given to every alkyl group and denote its position on the parent chain with the number.
4. The alkyl groups are written in alphabetical order.

Answer to Problem 15STP

Option (D) is correct that is 3-ethyl-2, 2, 3-trimethylpentane.

Explanation of Solution

The skeletal structure of compound:

1. The longest continuous chain contains five carbon atoms and the base name is pentane.
2. Two substituents that are two methyl groups are present on second carbon atom of the chain.
3. Two substituents that are ethyl and methyl group are present on third carbon atom of the chain.
4. The numbering for the substituents is given as: 2, 2, 3-trimethyl and 3-ethyl
5. Since, ethyl is starting with alphabet “e” thus, comes first in the naming of the compound.

Therefore, the name of the compound is 3-ethyl-2, 2, 3-trimethylpentane.

Hence, option (D) is correct.