A$.$ A CMFR is to be designed to remove contaminant A from water with a steady$-$state efficiency of $95\%.$

The decay reaction is zeroth order, with a rate constant of $0\mathrm{.}1M{h}^{-1}.$ The inlet concentration of $A$ is $0\mathrm{.}75$

M$.$ What hydraulic detention time is required to achieve the desired efficiency?

B$.$ Another CMFR is to be designed to remove contaminant B from water with a steady$-$state efficiency of

$95\%.$ The contaminant is consumed by a second$-$order decay reaction with a rate constant of $0\mathrm{.}005M^{-1}$

$s^{-1}.$ The inlet concentration of $B$ is $0\mathrm{.}75M,$ and the flow rate of water that must be treated is $0\mathrm{.}3m^3{s}^{-1}.$

How large must the reactor be$?$

C$.$ Contaminant $A$ is to be treated by a chemical reaction in a PFR$.$ If the reaction proceeds at a first$-$order

rate, what must be the hydraulic detention time be to achieve $95\%$ removal?