Component A diffuses through a stagnant film to the catalytic surface where it is instantaneously converted to B by the reaction A2B. Product B diffuses away from the catalytic surface, back through the stagnant film. The catalyst is considered a flat surface. The thickness of the stagnant film is and the mole fraction of A outside the stagnant film is yA0. Determine the rate at which A enter the gas film if this is a steady-state process and evaluate the concentration profile, that is, the distribution of mole fraction of A in the stagnant film