Halogenoalkanes are a homologous series with the general formula CnH2n+1X where X is F, Cl, Br or I. Halogenoalkanes contain carbon, hydrogen and at least one halogen atom. If the compound contains two or more halogen atoms when naming, they are listed in alphabetical order.Halogenoalkanes can be classified as primary secondary or tertiary depending on the number of alkyl groups joined to the carbon atom joined to the halogen atom.Halogenoalkanes are insoluble in water so many of their reactions are carried out using ethanol as a solvent.