1. Consider the biosensor device shown in the figure below. The biosensor is designed to measure the concentration of solute A in the well-mixed liquid phase. At the base of the device is an electrode of surface area 3.0cm2. The electrode is coated with an enzyme that catalyzes the reaction A2D. When solute A reacts to product D, product D is detected by the electrode, enabling for direct measurement of the flux of product D, which at steady state can be used to determine the concentration of A in the bulk liquid. The rate of reaction of A at the enryme surface is rapid relative to the rate of diffusion of A down to the surface. Directly above the enzyme-coated electrode is a 1.5cm thick (=4) gel layer that serves as a diffusion barrier for solute A and protects the enzyme. The gel layer is designed to make the flux of A down to the enzyme-coated surface diffusion limited. Above the gel layer is a well-mixed liquid containing a constant concentration of solute A,CA. The solubility of solute A in the liquid differs from the solubility of A in the gel layer. Specifically, the equilibrium solubility of A in the liquid layer (CA) is related to the solubility of A in the gel layer (C) by cn=K cu, with equilibrium partitioning constant K=0.5cm2 gel/ /cm3 liquid. The process is considered very dilute, and the total molar concentration of the gel layer is unknown. The concentration of product D in the well mixed liquid is very small so that cos0=0. The effective diffusion coefficient of component A in the gel is 1.9101cm2/s. Calculate the rate of production of product D,Wa, in mol/s if the concentration of solute A in the well-mbed liquid, chais 4.0104molcm1