32g of a sample of `FeSO_(4) .7H_(2)O` were dissolved in dilute sulphuric aid and water and its volue was made up to 1litre. 25mL of this solution required 20mL of `0.02 M KMnO_(4)` solution for complete oxidation. Calculate the mass% of `FeSO_(4) .7 H_(2)O` in the sample.

25 grams of a sample of ferrous sulphate is dissolved in dilute sulphuric acd. By adding water, its volume is made up to 1 litre. 25 mL of this solution requries 20 mL of N//10 KMnO_(4) solution for oxidation. Calculate the percentage of FeSO_(4) . 7H_(2)O in the sample. Strategy: Percentage of FeSO_(4).7H_(2)O =("mass"_("ferrous sulphate"))/("mass of sample")xx100% To get the mass of ferrous suphate, we need to calculate equivalents of ferrous sulphate. By law of equivalrnce, the milli equivalents of KMnO_(4) must be equal to the miliequivalents of ferrous sulphate. We can find the milliequivalents of KMnO_(4) by taking the product of millilitres of solution and its normality.

25 g of a sample of FeSO_(4) was dissolved in water containing dil. H_(2)SO_(4) and the volume made upto 1 litre. 25 mL of this solution required 20mL of N/ 10 KMnO_(4) for complete oxidation. Calculate % of FeSO_(4).7H_(2)O in given sample.

0.2828 g of iron wire was dissolved in excess dilute H_(2)SO_(4) and the solution was made upto 100mL. 20mL of this solution required 30mL of N/(30)K_(2)Cr_(2)O_(7) solution for exact oxidation. Calculate percent purity of Fe in wire.