$2.)$ A $90\%$ of $C{l}_2(A)$ present in a gas stream is required to be removed by absorption in water containing reactant $FeC{l}_2(B).C{l}_2$ and $FeC{l}_2$ react in the liquid as follows:

$C{l}_2(gi)+FeC{l}_2(l)FeC{l}_3(s),-r_A=k{C}_A{C}_B$

$FeC{l}_2$ has a negligible vapour pressure, hence does not go into the gas phase. What volume of agitated tank will you recommend for this operation? $(17\mathrm{.}5$ marks$)$

$D_A=D_B=3\mathrm{.}6{10}^{-6}{m}^{2}h,C_U=55,556mo\frac{l}{m^3},H_A={10}^{5}Pa*\frac{m^3}{m}ol,f_t=0\mathrm{.}9$

$F_g=90,000mo\frac{l}{h},P_T={10}^{6}Pa,P_{Ain}={10}^{4}Pa,P_{\text{A}\text{o}\text{u}\text{t}}={10}^{3}Pa,F_l=9000mo\frac{l}{h},$

$k=2\mathrm{.}6{10}^5\frac{m^3}{\text{m}\text{o}\text{l}\text{.}hr},C_{Bin}=5556mo\frac{l}{m^3},K_{Al}a=144h{r}^{-1},K_{Ag}a=0\mathrm{.}72mo\frac{l}{?}$

$a=200\frac{m^2}{m^3},(hr.m^3.Pa)$