A 1.0 g sample of Fe₂O₃ solid of 55.2% purity is dissolved in acid and reduced by heating the solution with zinc dust. The resultant solution is cooled and made upto 100.0 ml. An aliquot of 25.0 ml of this solution requires 17.0 ml of 0.0167M solution of an oxidant for titration. Calculate the number of electrons taken by the oxidant in the reaction of the above titration.

A mixture of H₂C₂O₄ (oxalic acid) and NaHC₂O₄ weighing 2.02 g was dissolved in water and solution made upto one litre. Ten millilitres of the solution required 3.0 ml. of 0.1 N sodium hydroxide solution for complete neutralization. In another experiment, 10.0 ml. of the same solution, in hot dilute sulphuric acid medium. require 4.0 ml. of 0.1 N potassium permanganate solution for complete reaction. Calculate the amount of H₂C₂O₄ and NaHC₂O₄ in the mixture.

Calculate the molality of 1 litre solution of 93% H₂SO₄ (weight/volume). The density of the solution is 1.84 g/ml

A solid mixture (5.0 g) consisting of lead nitrate and sodium nitrate was headed below 600^oC until the weight of the residue was constant. If the loss in weight 28.0 percent, find the amount of lead nitrate and sodium nitrate in the mixture.