A process for co-production of 1,1,1,2-tetrafluoroethane (HFC-134a;CF.sub.3 CH.sub.2 F), pentafluoroethane (HFC-125; CF.sub.3 CHF.sub.2) and 1,1,1 -trifluoroethane (HFC-143a; CF.sub.3 CH.sub.3) by a two-step gaseous reaction comprising the steps of a) reacting 1,1,1-trifluoro-2-chloroethane (CFCH.sub.2 Cl, HCFC-133a) with HF in a first reactor to prepare 1,1,1,2-tetrafluoroethane (HFC-134a; CF.sub.3 CH.sub.2 F), pentafluoroethane (HFC-125; CF.sub.3 CHF.sub.2) and 1,1,1-trifluoroethane (HFC-143a; CF.sub.3 CH.sub.3); b) adding trichloroethylene (TCE:CCl.sub.2 CHCl) to the reaction product of step a) in a second reactor to prepare HCFC-133a; separating HCl, HFC-134a, HFC-125 and HFC-143a from the reaction product of step b) and recycling HCFC-133a to the first reactor, and the stages being performed in the presence of fluorization catalyst obtained by calcining a reaction product which is obtained by reacting ethanol with a mixture of calcium fluoride(CaF.sub.2) with an aqueous solution of chromium trioxide, zinc chloride and ferrous chloride is provided.