Question

The IUPAC name of $C{{H}_{3}}CH\left( C{{H}_{2}}C{{H}_{3}} \right)C{{H}_{2}}C{{H}_{3}}$ is:
A.$1,1-$ methyl ethyl propane
B.$2-$ ethylbutane
C.$1-$ methyl$-1-$ ethyl propane
D.$3-$ methylpentane

Answer 1

Hint: In organic chemistry, nomenclature is a term that contains a set of rules to form organic compounds. It is used to name a compound and make organic chemistry easy. The full form of IUPAC is the International Union of Pure and Applied Chemistry.

Complete step-by-step answer:IUPAC of an organic compound uses a systematic approach that is taken from nomenclature. The need for these types of systematic approach is due to the discoveries of new organic compounds. On the basis of the structure of a compound, an organic name is suggested by following the set of rules of nomenclature. Sometimes IUPAC names are simpler than the old name of the compounds. Let us take an example- the IUPAC has given the ethanol but the older name was ethyl alcohol.
For the formation of an organic compound using systematic method, firstly we select the name of the parent structure. This name can be modified by prefixes, suffixes.
To write the IUPAC name of the compound, let us see the general way of writing the name-
Locant $+$ prefix $+$ root $+$ locanto $+$ suffix
Let us discuss about the names used in general formula in details,
Root- it is defined as the total number of carbon atoms present in the longest carbon chain.
Suffix- a functional group belongs to a molecule which follows the root of the name. For example- ol, al, ane.
Prefix- it is added prior to the root of the compound in a IUPAC name. For example- cyclo, methyl.
In this question, we have to write the IUPAC name of $C{{H}_{3}}CH\left( C{{H}_{2}}C{{H}_{3}} \right)C{{H}_{2}}C{{H}_{3}}$ . So according to the above general way of writing the IUPAC name-
The longest carbon chain contains five carbon atoms. There is a presence of a methyl group in carbon three. Therefore the name of this compound is $3-$ methylpentane.

Hence the correct option is D.

Note:There are many methods of IUPAC nomenclature-
Compositional nomenclature- It is used to name the compounds based on composition of the species.
Substitutive nomenclature- In this the parent hydride is replaced by the hydrogen atoms with a substituent group.
Additive nomenclature- This method is used primarily for nomenclature of coordination compounds.