25g of a sample of ferrous sulphate was dissolved in water containing dilute h2s04 and the volume made up to one litre. 25ml of this solution required 20ml of N/10 kmn04 solution for complete oxidation. calculate the percentage of fe204 7h20 in the sample.
My calculation 0.02x 0.1 = 0.002
0.002 x 1000ml x 293g/mol/ 25ml = 23.44
23.44/25g x 100% = 93.76%
the right answer 88.96%