IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry - [admin]: numerical: Calculate the percentage of Fe2O3 and Fe3O4 in sample

tarun_bits

A 3.00 g sample containig Fe3O4 , Fe2O3 and an inert impure substance, is treated with excess KI solution in prescence of dil H2SO4. The entire iron is converted into Fe2+ along with 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 Na2 S2 O3 solution to reduce the iodine present. A 50 mL of the diluted solution, after comlete extraction of the iodine requires 12.80 ml of 0.25 M KMnO4 solution in dilute H2 SO4 medium for the oxidation of Fe 2+ . Calculate the percentage of Fe2O3 and Fe3O4 in the original sample.

tarun_bits

anyone plz

tarun_bits

WHOEVER WILL SOLVE THIS WILL BE GREAT GENIUS......

atleast try

tarun_bits

take rates right away

tarun_bits

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aankurverma

let moles of Fe+2 = a and Fe+3 = b

FeO.Fe2O3 = Fe3O4

KI

Fe3O4 + Fe2O3

Fe+3(2a + 2b) + I2(nmoles0

Fe+2

100ml

2a + 2b = 5*11*0.5*2

out of 100ml 50 ml is taken out and converted the rest into Fe+2 (3a + 2b)

3a + 2b = 2*12.80*0.25*5

now solve a and b and get the percentage composition

do rate me if m correct

tarun_bits

tell the correct answer

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