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.

An equal volume of a reducing agent is titrated separately with 1M KMnO₄ in acid neutral and alkaline media. The volumes of KMnO₄ required are 20 ml. in acid 33.4 ml. neutral and 100 ml in alkaline media. Find out the oxidation state of manganese in each reduction product. Give the balanced equations for all three half reactions. Find out the volume of 1M K₂Cr₂O₇ consumed; if the same volume of the reducing agent is titrated in acid medium.

A sugar syrup of weight 214.2 g contains 34.2 g of sugar (C₁₂H₂₂O₁₁). Calculate (i) molal concentration and (ii) mole fraction of sugar in the syrup

A sample of hydrazine sulphate (N₂H₆SO₄) was dissolved in 100 ml. of water, 10 ml of this solution was reacted with excess of ferric chloride solution and warmed to complete the reaction. Ferrous ion formed was estimated and it required 20 ml of M/50 potassium permanganate solution. Estimate the amount of hydrazine sulphate in one litre of the solution.

Reaction:

4Fe³⁺ + N₂H₄ $$\to$$ N₂ + 4Fe²⁺ + 4H⁺

$$MnO_4^-$$ + 4Fe²⁺ + 8H⁺ $$\to$$ Mn²⁺ + 5Fe³⁺ + 4H₂O