The major product of the reaction between a primary alcohol R-CH2OH and an excess of hydrogen halide HX in the presence of a strong acid catalyst is an alkyl halide R-CH2X , where R is the alkyl group and X is the halide. This reaction is known as nucleophilic substitution, specifically an SN1 or SN2 mechanism depending on the structure of the alkyl group R . In this case, since it is a primary alcohol, the reaction will likely proceed via an SN2 mechanism.