Special Problems $-$ cont' $d^1$

$2.$ An ammonia$-$air mixture frac ammonia$)$ is to be scrubbed with water at $293K.$ The final mol frac is $0\mathrm{.}00041$ ammonia. Both the liquid and gas flow rates are $1\mathrm{.}36{10}^{-3}k\frac{g}{m^2}-s.$ Determine the no$.$ of equilibrium stages needed. The equilibrium data for partial pressures of ammonia over aqueous ammonia solutions is are:

$P_A(atm),0\mathrm{.}016,0\mathrm{.}024,0\mathrm{.}042,0\mathrm{.}066,0\mathrm{.}218$

$\frac{kgNH3}{100(kg)water},2,3,5,7\mathrm{.}5,20$