The irreversible elementary gas phase reaction $2$AlongrightarrowB$+C$ is carried out in a packed bed reactor containing $100kg$ of catalyst. The entering pressure is $20$atm and the exit pressure is $4$atm. Pure A enters at a volumetric flow rate of $18d\frac{m^3}{m}in.$ The entering concentration of $A,C_{A0}=0\mathrm{.}25mo\frac{l}{d}{m}^3$ and the specific reaction rate constant, $k=1\mathrm{.}5d\frac{m^6}{m}ol*kg*min.$ Calculate the exit conversion.