A process for making 2-chloro-1,1,1,2-tetrafluoropropane. The process has the step of contacting 2-chloro-3,3,3-trifluoropropene with hydrogen fluoride in the presence of a catalyst having about 25 to about 99.9 mole percent antimony pentachloride and about 0.1 to about 75 mole percent of a metal of a Lewis acid under conditions sufficient to form the 2-chloro-1,1,1,2-tetrafluoropropane. There is a second process for making 2-chloro-1,1,1,2-tetrafluoropropane. The process has the step of hydrofluorinating about 75 to about 99.9 mole percent 2-chloro-3,3,3-trifluoropropene and about 0.1 to about 25 mole percent of one or more other hydrocarbons having at least one chlorine atom in the presence of a catalyst of fluorinated antimony pentachloride under conditions sufficient to form the 2-chloro-1,1,1,2-tetrafluoropropane. There is yet another process for hydrofluorinating 2-chloro-3,3,3-trifluoropropene to 2-chloro-1,1,1,2-tetrafluoropropane. The process has the step of contacting the 2-chloro-3,3,3-trifluoropropene with hydrogen fluoride in the presence of a vapor phase catalyst under conditions sufficient to form the 2-chloro-1,1,1,2-tetrafluoropropane.