In the text, we used the film theory to show that for a fast irreversible second-order reaction,

This derivation assumed implicitly that the system was always dilute, so that there was no diffusionengendered convection (i.e., n₁ = j₁). Imagine, instead, that the solution is concentrated, diluted only with product c₃. The stoichiometry is simple:

Find the mass transfer coefficient in this case, assuming that diffusion obeys binary equations, with diffusion coefficients that are the same for all species.

k0k=1+D1c10D2c20 ( species 1)+( species 2)( species 3)