Problem $5.($Completely mixed flow reactor$)$ Calculate the hydraulic residence time and volume of a CMFR required to achieve the given effluent concentration for the reaction given below. Q is a flow rate of inflow and effluent, CI and CE are the concentrations of inflow and effluent, respectively and kis a reaction rate constant. a$.$ Q $=38$ ML$/$d$,$ CI $=100\backslash$mu g$/$L$,$ CE $=2\mathrm{.}0\backslash$mu g$/$L$,$ first$-$order decay reaction, k $=0\mathrm{.}375$ min$1.$b$.$ Q $=190$ ML$/$d$,$ CI $=15$ mg$/$L$,$ CE $=1\mathrm{.}8$ mg$/$L$,$ first$-$order decay reaction, k $=0\mathrm{.}057$ min$1.$c$.$ Q $=5000$ m$3/$d$,$ CI $=55\backslash$mu g$/$L$,$ CE $=21\backslash$mu g$/$L$,$ second$-$order decay reaction, k $=0\mathrm{.}0075$ L$/$mg$$min