Question

The IUPAC name of neopentane is:
(A) $2,2 - {\text{dimethylpropane}}$
(B) $2 - {\text{methylpropane}}$
(C) $2,2 - {\text{dimethylbutane}}$
(D) $2 - {\text{methylbutane}}$

Answer 1

The name neopentane is the common name of the organic compound. Here the neo compounds are the compounds in which the second to the last carbon chain has three methyl groups attached to it or the carbon atom is tri-substituted.

Complete step by step answer:
In the question, we don’t have any structure so that we can easily give the IUPAC name to the compound. For simplicity the organic compounds are given a common name. So, here the common name of the compound is given to us which is neopentane. So as the common name contains pentane we can conclude that there are a total of five carbon atoms in the compound. Now we will try to understand the possible structure of neopentane. We know that in neo compounds the second to the last carbon atom is tri-substituted and the substituents are the three methyl groups. So from the common name neopentane, we can conclude that the parent chain of the compound will contain their carbon atoms and we know that in neo compounds the second carbon atom is tri-substituted. So the chemical structure of the compound neopentane will be as given below.

Now we have the structure of the compound so we easily give it an IUPAC name following the basic rules of nomenclature. The second carbon atom is attached with two methyl groups as the parent chain contains three carbon atoms. Hence, the IUPAC name is $2,2 - {\text{dimethylpropane}}$ .
Therefore, the correct option is (A).

Note:
The molecular formula of the compound neopentane is ${C_5}{H_{12}}$ . There are three different structural isomers of the molecular formula ${C_5}{H_{12}}$ namely pentane, isopentane, and neopentane. Neopentane is an inflammable gas at room temperature.