$P4-15$ A It is desired to carry out the gaseous reaction $A$

$B$ in an existing

tubular reactor consisting of $50$ parallel tubes $40ft$ long with a $0\mathrm{.}75-in.$ inside

diameter. Bench$-$scale experiments have given the reaction rate constant for

this first$-$order reaction as $0\mathrm{.}00152s^{-1}$ at $200F$ and $0\mathrm{.}0740s^{-1}$ at $300F.$ At

what temperature should the reactor be operated to give a conversion of $A$ of

$80\%$ with a feed rate of $500l\frac{b}{h}$ of pure A and an operating pressure of

$100$ psig? A has a molecular weight of $73.$ Departures from perfect gas behav$-$

ior may be neglected, and the reverse reaction is insignificant at these condi$-$

tions. $($Ans$.$: $T=275F.)($From California Professional Engineers Exam.$)$