Interphase mass transfer has been analyzed for a reactant being transferred from a sphere into a quiescent, infinite continuous phase where it undergoes a chemical reaction. Ranges of the diffusivity ratio D, the distribution coefficient H, and the Damkohler number Da have been delineated, within which the overall resistance to mass transfer may be reasonably ascribed to the sum of the individual resistances in each of the two phases. Outside these parameter ranges, the resistances for two decoupled mass transfer problems may not be added to give the overall resistance to the coupled mass transfer problem. An alternative procedure for decoupling the conjugate problem is proposed and an expression for the upper bound for the overall mass transfer rate established. Also, because chemical reactions are widely used to enhance interphase mass transfer, we present minimum rates of reaction Da for given physical properties D and H that will produce maximum rates of mass transfer.