Question

1 mole of potassium permanganate and 1 mole of ferrous sulfide are reacted in presence of excess hydrochloric acid, how many moles of Ferric sulfate will produce?

(a) 10/18

(b) 5/18

(c) 1/18

(d) 1/36

This question was addressed to me in final exam.

This intriguing question originated from Stoichiometry Applications Terminology in chapter The Chemical Reaction Equation & Stoichometry, Material Balances for Processes Involving Reaction and Multiple Units of Basic Chemical Engineering

Answer 1

Correct choice is (b) 5/18

The explanation is: The balanced chemical reaction is 18KMnO4 + 10FeS + 32H2SO4 -> 18MnSO4 + 5Fe2(SO4)3 + 9K2SO4 + 32H2O, => KMnO4 is limiting reagent, => moles of Fe2(SO4)3 = (5/18)*1 = 5/18.