A quantity of 1.0 g sample of Fe₂O₃ solid of 55.2 per cent purity is dissolved in acid and reduced by heating the solution with zinc dust. The resultant solution is cooled and made up to 100 ml. An al

Question

A quantity of 1.0 g sample of Fe₂O₃ solid of 55.2 per cent purity is dissolved in acid and reduced by heating the solution with zinc dust. The resultant solution is cooled and made up to 100 ml. An aliquot of 25 ml of this solution requires 17 ml of 0.0167 M solution of an oxidant for titration. The number of electrons taken up by the oxidant in the reaction of the above titration is

TestHub · Accepted Answer

Fe₂O₃ = 1.0 × 0.552 = 0.552 g = 0.552/160 = 3.45 mmol, so Fe²⁺ = 6.9 mmol in 100 ml; 25 ml aliquot holds 1.725 mmol Fe²⁺, releasing 1.725 mmol e⁻ (Fe²⁺ → Fe³⁺). Oxidant = 0.0167 × 0.017 = 0.284 mmol. Electrons per oxidant molecule = 1.725/0.284 ≈ 6. Ans: 6.

Chemistry - Redox Reactions Question with Solution | TestHub

Doubts & Discussion