Gas A diffuses from point $1$ at a partial pressure of $10\mathrm{.}325$kPa to point $2$ at distance $4$

$mm$ away. At point $2,$ it has chemical reaction on the catalyst surface with reaction of

$A3B.$ Component $B$ diffuses back instantaneously at steady state. The total pressure

is $101\mathrm{.}325$kPa. The temperature is $300K$ and $D_{AB}=0\mathrm{.}275{10}^{-4}\frac{m^2}{s}.(25$ points$)$

a$)$ Report $x_2$ and calculate $N_{}.$

b$)$ Assume the reaction is slow with surface reaction velocity $k^{\text{'}}=3\mathrm{.}45{10}^{-3}\frac{m}{s}.$ Calculate

$x_{A2}$ and $N_A.$