A reactor is supplied with two steams with equal flow rates, stream-1 containing 75% SO2, 25% N2 and stream-2 containing pure H2S, if the product has 1200 grams of S, and the ratio of H2S to H2O is 5 and the ratio of SO2 to H2S is 2, what fraction of limiting reagent is converted into product?

Correct Answer:
The reaction is 2H2S + SO2 -> 3S + H2O, => extent of reaction, E = (1200/32)/3 = 12.5, Let the rate be F. nSO2p = 2nH2Sp, => 0.75F – E = 2(F – 2E), => 1.25F = 3(12.5), => F = 30 moles, => limiting reagent is H2S, => fraction of H2S converted into product = 2E/F = 2(1.25)/3 = 0.83.