Pyrite (FeS2) is converted to sulphuric acid with an overall yield of 90% through the sequence FeS2 -> SO2 -> SO3 -> H2SO4 (all sulphur ends up as H2SO4 in 100% yield). Taking Fe = 56, S = 32, O = 16, H = 1, calculate the mass of H2SO4 obtained from 80.0 g of pure FeS2. Give the answer in grams to one decimal place.

JEE Main levelNumerical answerDifficulty 2 of 3pn082

Pyrite ( $FeS X_{2}$ ) is converted to sulphuric acid with an overall yield of 90% through the sequence $FeS X_{2} SO X_{2} SO X_{3} H X_{2} SO X_{4}$ (all sulphur ends up as $H X_{2} SO X_{4}$ in 100% yield). Taking Fe = 56, S = 32, O = 16, H = 1, calculate the mass of $H X_{2} SO X_{4}$ obtained from 80.0 g of pure $FeS X_{2}$ . Give the answer in grams to one decimal place.

Numerical answer type, answer in g, tolerance 0.05.

Molar mass of

FeS X_{2}

= 120 g/mol, so 80.0 g = 0.6667 mol. Each

FeS X_{2}

gives 2

H X_{2} SO X_{4}

(molar mass 98): theoretical mass = 0.6667 x 2 x 98 = 130.67 g. At 90% yield the mass is 117.6 g.