It is desired to carry out the gaseous reaction A B in an existing tubular reactor consisting of 50 parallel tubes 40 ft long with a 0.75-in. inside diameter. Bench-scale experiments have given the reaction rate constant for this first-order reaction as 0.00152 s-1 at 200°F and 0.0740 s-1 at 300°F. At what temperature should the reactor be operated to give a conversion of A of 80% with a feed rate of 500 Ib/h of pure A and an operating pressure of 100 psig? A has a molecular weight of 73. Departures from perfect gas behavior may be neglected, and the reverse reaction is insignificant at these conditions.