Question

A 1.0 g sample of Fe₂O₃ solid of 55.2% purity is dissolved. in acid and reduced by heating the solution with zinc dust. The resultant solution is cooled and made upto 100.0 mL. An aliquot of 25.0 mL of this solution requires for titration. Calculate the number of electrons taken up by the oxidant in the reaction of the above titration.

Answer 1

The redox changes are : for reduction of Fe₂O₃ by zinc dust

= meq of oxidant used to oxidize Fe²⁺ again

:. Meq of Fe₂O₃ in 25 mL = meq of oxidant

= 17 x 0.0167 x n

where, n is the number of electrons gained by 1 molecule of oxidant

Hence, number of electrons gained by one molecule of oxidant = 6