Analytical and exact solutions for the concentration distribution and Sherwood number of the reactant and the intermediate product in convective diffusion of power law fluids in parallel plates and tubular reactors with consecutive homogeneous and catalytic wall reactions are developed. Closed-form expressions have also been obtained for the conversion of the reactant as well as the yield of the intermediate product. The problem of solving the equation of conservation of mass for each component was transformed to that of solving an eigenvalue problem using the finite-integral transform technique, and as many eigenvalues and eigenfunctions as needed are determined using the sign-count method. The accuracy of the solutions is established and the effects of power law index, and the homogeneous and heterogeneous reactions parameters on mass transfer variables are examined.