A process for the production of pentafluoroethane is described. The process comprises reacting perchloroethylene with hydrogen fluoride in the vapour phase in a first reactor or a first plurality of reactors in the presence of a fluorination catalyst to produce a composition comprising dichlorotrifluoroethane, hydrogen chloride, unreacted hydrogen fluoride and perchloroethylene. This composition is subjected to a separation step to yield a purified composition comprising at least 95 weight % of dichlorotrifluoroethane and less than 0.5 weight % of compounds having the formula C 2 C 16-X F X , where x is an integer of from 0 to 6, based on the total weight of organic compounds in the composition. The composition from the separation step is then reacted with hydrogen fluoride in the vapour phase in a second reactor or a second plurality of reactors in the presence of a fluorination catalyst to produce a composition comprising pentafluoroethane and less than 0.5 weight % of chloropentafluoroethane, based on the total weight of organic compounds in the composition.