Question

write the IUPAC name of the compound.

Answer 1

The IUPAC nomenclature of organic chemistry is a system of organic chemical compounds in the nomenclature of chemicals as stated by the International Union of Pure and Applied Chemistry. Informally we call it Blue Book. The book mentions certain rules for the naming of compounds having functional groups.

Complete step by step answer:
Benzene is an aromatic compound with the formula ${C_6}{H_6}$. When one or more than one hydrogens of benzene are replaced by any groups then several compounds are formed. Now for the IUPAC nomenclature at first, we prefix the name of a substituent to the word benzene. For example, chlorobenzene, methylbenzene, etc.
Now when more than one group is present, at first find out the main compound then give the number to other groups in such a way that they get fewer numbers. Or if there is now base compound then give numbers according to the alphabetical order.
Now for the given compound, the base compound is methylbenzene. The numbering is as follows,

Now according to the numbering, the IUPAC name of this compound is, 3-chloro-4-nitromethylbenzene.
Methyl benzene is also known as toluene.
So, the IUPAC name of this compound can be written as, 3-chloro-4-nitrotoluene.

Additional information:
In the IUPAC nomenclature case, the root word is the number of total carbons in the longest chain of that compound.

No. of carbons	Root word
1	meth
2	eth
3	prop
4	but
5	pent

… and so on.
The primary suffix is used to differentiate between the saturated compounds (Alkanes) and unsaturated compounds (Alkene and Alkynes).

compound	suffix
Alkane	ane
Alkene	Ene
Alkyne	Yne

If there is more than one suffix. Then one of those suffixes is considered as the secondary suffix.
Example: Methanol (Alkanol), here ‘ol’ is a secondary suffix.
The primary prefixes are used to differentiate between cyclic compounds and noncyclic or chain compounds. For cyclic compound prefix s ‘cyclo’. if there are any side chains or groups are present then secondary prefixes like ‘methyl’, ‘ethyl’, ‘propyl’, ‘isopropyl’ are used.

Note: One must remember that every substituent should have a number and in the case of aromatic compounds, the positions with respect to the first one is known as ortho $\left( {1,2;1,6} \right)$, meta $\left( {1,3;1,5} \right)$, and para $\left( {1,4} \right)$. Use of commas to separate numbers and hyphens to separate numbers and substituents is done while writing the formula.