Calculate the volume of 0.05 M KMnO4 solution required to oxidize completely 2.70 g of oxalic acid in acidic solution.
The equation representing the chemical change is 2KMnO4 + 3 H2SO4 → K2SO4 + 2 MnSO4 + 3 H2O = 5[0] H2C2O4 + [O] → 2 CO2 + H2O × 5 Step I. To calculate the no. of moles of KMn04 required to completely oxidize 2.70 g of’H2C2O4 in acidic medium: Molar mass of H2C2O4 = 2 × 1 +2 × 12 + 4 × 16 = 90.0 g mol-1 ∴ No. of moles of H2C2O4 contained in 2.70 g of it = 2.7090.0 = 0.03 5 Moles of H2C2O4 are oxidized by 2 moles of KMnO4 ∴ 0.03 moles of it oxidized by = 25 × 0.03 = 0.012 mole of KMnO4 Step II. To calculate the volume of 0.05 M KMnO4 solution Now 0.05 mole of KMnO4 are contained in 1000 cm3 of solution ∴ 0.012 mole of KMnO4 will be contained in 10000.05 × 0.012 = 240 cm3 of solution Thus, the required volume of 0.05 M KMnO4 solution = 240 cm3.
