Question

Tert-butyl group is named as:
(A) ${\text{1,1 - dimethylethyl}}$
(B) ${\text{2,2 - dimethylethyl}}$
(C) ${\text{1,2 - dimethylethyl}}$
(D) ${\text{1,2,3 - trimethylmethyl}}$

Answer 1

Hint: First we will draw the structure of the Tert-butyl group which satisfy the valencies of the carbon and then we will do the nomenclature of the group according to the International Union of Pure and Applied Chemistry (IUPAC).

Complete step by step answer:
Firstly, we will see the structure of the tert-butyl group
  

The above structure is tert-butyl group. The tert-butyl is a common name not the IUPAC name. To name a compound we follow the rules framed for naming a compound so that a compound has a unique name but also easy to learn and understand due to a trend.
IUPAC Rules
1.The longest chain of carbon is taken as the main chain which forms the principal name of the compound.
2.The numbering of the group should be done in such a way that the sum of the number of all the groups should be small.
3.The substituted group should be put according to the alphabetical order to omit any priority or special treatment to a group.
4.Here the longest chain is of $2$ carbon and the substituted groups are present on the same carbon so the numbering will be the same.
5.Because of the longest chain is of two carbon so the root name will be eth- , we see that the group have one free valency so it will become ethyl group

So, the name of the above group is (A) 1,1-dimethylethyl.

Note: The naming of every compound and group is according to the IUPAC rules due to which every compound has a different and unique name. If we know the rules properly, we can name all types of compound easily

There should be no space between the alphabets in the name of the compound. The numbers should always be separated by comma. There should be a hyphen separation between a number and alphabet. These $3$ rules should always be followed while writing.