Alkyl halides are the derivatives of alkanes which can be obtained by replacing one hydrogen atom by halogen atom. The general formula of monohalogen derivative of alkanes is CnH2n+1X (where X is any halogen atom). The monohalogen derivatives of alkanes are commonly called as alkyl halides. Common names of alkyl halides are derived from the name of parent hydrocarbon.
Alkyl halides are derivatives of arenes by replacing one hydrogen atom by halogen atom. Aryl halides does not have general formula like alkyl halides. For example.