Question

What are the IUPAC rules for naming alkyl halides?

Answer 1

The IUPAC system is the most rational and widely used system of nomenclature in organic chemistry and the most important feature of the system is that any given molecular structure has only one IUPAC name.

Complete step by step answer:
Alkyl halides are organic compounds in which one or more than one hydrogen atom is replaced by an equal number of the halogen atom in an aliphatic hydrocarbon chain. Alkyl halides are also known as haloalkanes. In haloalkanes, halogen atoms are attached to the $sp^3$ hybridized carbon atom of an alkyl group.
As per the IUPAC system for the case of monohalogen derivative, the individual names are derived by prefixing the word “halo” to the name of the longest straight chain alkane. The numbering of the parent straight-chain alkane is always done in such a way that the carbon atom carrying the halogen atom gets the lowest possible number. The IUPAC name of the monohalogen derivative is written in one word. In the case of dihalogen and polyhalogen derivative, they are named as dihaloalkanes and polyhaloalkane in which the position for the halogen, after being repeated twice, thrice, etc, is prefixed to the name of the dihaloalkane and polyhaloalkane.
If there are different halogens attached to the carbon atom in the hydrocarbon chain, the IUPAC name is obtained by prefixing the name of each halogen in alphabetical order along with its locant to the name of the parent alkane.

Note:
IUPAC nomenclature is abbreviated to the International Union of Applied Chemistry system of nomenclature and it was introduced as due to a large number of organic compounds, it was very difficult to remember the common or trivial name for each compound. Also, the IUPAC system helps standardize the naming of organic compounds.