An absorption tower contains $10$ actual trays and is being used to absorb $S{O}_2$ from air by pure water a

$293K$ and $1\mathrm{.}013{10}^{5}Pa.$ The entering gas contains $20$mol$\%S{O}_2$ and the inlet air flow rate is $150kg$

inert air$/$h$.$ The entering water rate is $6000k\frac{g}{h}.$ Assume Raoult's law apply. If $75\%$ of the $S{O}_{2}i$

recovered,

a$.$ Determine the outlet composition of the gas stream.

b$.$ Determine the number of equilibrium stages using graphical approach.

c$.$ Repeat part$($b$)$ using the Kremser method.

d$.$ What is the overall column efficiency, $E_0?$