When a reaction is nearly instantaneous it is often mixing limited, i.e. the product yield is dependent on how fast the reactants are brought together. This effect of mixing is especially evident in the case of a competitive-consecutive reaction scheme where the product of the desirable reaction reacts with one of the reactants to form undesirable by-products. This kind of reaction mechanism can result in large yields of undesirable by-products, sometimes up to two or three times the yield of the desired product. A 1-D, non-dimensional, diffusion-reaction model at the micro-mixing scale has been developed to attempt to characterize this reactive-diffusive system. Constant density and diffusivities were assumed and the system of PDE's was solved using COMSOL 3.4. It was found that the ratio of rate constants of the reactions, the stoichiometry of the reactions, and the mixing timescale have considerable effects on the yield of desirable product.