SO3 is produced by oxidation of SO2 in the presence of air. SO2 is mixed with air so that the molar ratio of SO2 to oxygen is 1:1.2 and is passed through a reactor at 1 bar, 850 K, until equilibrium is established. To improve conversion, SO3 is separated out of the product mixture, while a portion of the other gases (SO2 , O2 , and N2 ) is recycled back into the reactor with the rest being used elsewhere in the plant. Assuming that all of the SO3 is obtained at the exit of the separator in pure form (i.e., no oxygen or nitrogen are present), determine the flow rate of the recycle stream (per 100 mol in the feed) that is required to produce an overall conversion of 95% and report the per-pass conversion of the reactor.