0.49 g of K2Cr2O7 (molar mass 294) is used in acidic medium to oxidise Fe^2+ to Fe^3+. The mass of iron(II) oxidised is (Fe = 56):

JEE Main levelSingle correct optionDifficulty 2 of 3rx179

0.49 g of $K X_{2} Cr X_{2} O X_{7}$ (molar mass 294) is used in acidic medium to oxidise $Fe X^{2 +}$ to $Fe X^{3 +}$ . The mass of iron(II) oxidised is (Fe = 56):

mmol of dichromate = 0.49/294 x 1000 = 1.667. Each dichromate accepts 6 electrons, so mmol

Fe X^{2 +}

= 10.0. Mass = 10.0 mmol x 56 = 560 mg = 0.56 g.