Water containing dilute contaminant $A,C_1=0\mathrm{.}03$kmo$\frac{l}{m^3},$ is flowing past a $30m$ thick membrane

$(K^{\text{'}}=1\mathrm{.}5,D_A=7{10}^{-11}\frac{m^2}{s},C_2=0\mathrm{.}005$kmo$\frac{l}{m^3}).k_{C1}$ is large $k_{C2}=2\mathrm{.}02{10}^{-5}\frac{m}{s}.$

a$)$ Derive equation to calculate $N_A$ at steady state and sketch profiles.

b$)$ Calculate flux and interface concentrations and check relative values of concentrations

guessed in a$).$