$7\mathrm{.}2-3.$ Absorption of $H_{2}S$ by Water. In a wetted$-$wall tower an air $-H_{2}S$ mixture is flowing by a film of water that is flowing as a thin film down a vertical plate. The $H_{2}S$ is being absorbed from the air to the water at a total pressure of $1\mathrm{.}50$atm abs and $30C.$ A value for $k_c^{\text{'}}$ of $9\mathrm{.}567{10}^{-4}\frac{m}{s}$ has been predicted for the gas$-$phase mass$-$transfer coefficient. At a given point the mole fraction of $H_{2}S$ in the liquid at the liquid$-$gas interface is $2\mathrm{.}0({10}^{-5})$ and $p_A$ of $H_{2}S$ in the gas is $0\mathrm{.}05$atm. The Henry's law equilibrium relation is $p_A(atm)=609x_A($mole fraction in liquid$).$ Calculate the rate of absorption of $H_{2}S.($Hint: Call point $1$ the interface and point $2$ the gas phase. Then calculate $p_{A1}$ from Henry's law and the given $x_A.$ The value of $p_{A2}$ is $0\mathrm{.}05$atm.$)$

Ans. $,N_A=-1\mathrm{.}485{10}^{-6}$kgmo$\frac{l}{s}*m^2$