(N/A) Haloalkanes exhibit three types of isomerism:
$(i)$ Chain isomerism: When two or more haloalkanes with the same molecular formula differ in the length of the carbon chain,they are called chain isomers.
Example: $CH_3-CH_2-CH_2-CH_2-Cl$ ($1$-chlorobutane) and $CH_3-CH(CH_3)-CH_2-Cl$ ($1$-chloro-$2$-methylpropane).
$(ii)$ Position isomerism: When two or more haloalkanes with the same molecular formula differ in the position of the halogen atom attached to the carbon chain,they are called position isomers.
Example: $CH_3-CH_2-CH_2-Cl$ ($1$-chloropropane) and $CH_3-CHCl-CH_3$ ($2$-chloropropane).
$(iii)$ Optical isomerism: Haloalkanes that have the same molecular and structural formula but differ in the spatial arrangement of atoms or groups around a chiral carbon atom,resulting in the rotation of plane-polarized light,are called optical isomers.
Example: The two enantiomers of $2$-chlorobutane.