$($Welty $27\mathrm{.}21)$ Consider a rectangular$-$shaped gel tablet of thickness $0\mathrm{.}652cm,$ width of $1\mathrm{.}0cm$

and depth of $1\mathrm{.}0$ loaded with the drug Dramamine. The edges of the gel tablet are sealed so that

diffusion of Dramamine occurs only along the thickness of the gel tablet. The initial

concentration of the drug Dramamine $($solute $A)$ in the gel $(B)$ is $64\mathrm{.}0m\frac{g}{c}{m}^3,$ to provide a total

drug dosage of $41\mathrm{.}7mg.$ The concentration of the drug at the exposed surface of the tablet is

maintained at zero to provide a constant sink for mass transfer. The diffusion coefficient of the

drug in the gel is $3\mathrm{.}0{10}^{-7}c\frac{m^2}{s}.$

a$)[$ChE$312$ Assignment$]$ Analytically determine an equation for the concentration profile of $A$

$W^{\text{i}\text{t}\text{h}\text{i}\text{n}\text{t}\text{h}\text{o}\text{a}\text{a}\text{l}}$