A 3.00 g sample containing Fe_3O_4, Fe_2O_3 and an inert impure substance, is treated with excess of KI solution in pr

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Q 1159167914.     A 3.00 g sample containing Fe_3O_4, Fe_2O_3 and an inert impure substance, is treated with excess of KI solution in presence of dilute H_2SO_4. The entire iron is converted into Fe^(2+) along with the liberation of iodine. The resulting solution is diluted to 100 mL. A 20 mL of the diluted solution requires 11.0 mL of 0.5 M Na_2S_2O_3 solution to reduce the iodine present. A 50 mL of the dilute solution, after complete extraction of the iodine required 12.80 mL of 0.25 M KMnO_4 solution in dilute H_2SO_4 medium for theoxidation of Fe^(2+). Find the percentage of Fe_2O_3 and Fe_3O_4 in the original sample respectively.

JEE 1996
A

44.12 % , 34.80 %

B

49.33 % , 34.80 %

C

49.33 % , 28.10 %

D

44.12 % , 28.10 %

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