Diffusion in a Liquid Film with a Zeroth-Order Reaction A liquid film resting on a surface is brought into contact with a gas mixture at t=0. A component of the gas which is not present initially in the liquid is absorbed and undergoes a zeroth-order reaction (i.e., with a constant rate whenever the reactant is present). (a) Define the Damkhler number used here (b) Evaluate the steady-state concentration profile, ss(x), and determine Da, the maximum value of Da for which the proposed problem formation is valid