Question

Potassium permanganate is prepared from the minera lpyrolusite, `MnO_(2)`. Its crystals have deep purple colour. It acts as an oxidizing agent in the neutral, alkaline as well as acidic medium. In acidic medium , it is used in volumetric analysis for estimation of ferrous salts, oxalates etc. The titrations are carried out in presence of `H_(2)SO_(4)`. However ,before using itas a titrant, it is first standized with standard oxalic acid solution or Mohr salt solution. In one of the experiments on titration , 13.4 g of dry pure sodium oxalate ( molar mass `=134 g mol^(-1)` ) was dissolved in 100mL of distilled waterand then 100 mL of 2M `H_(2)SO_(4)` were added. The solution, was cooled to `25.30^(@) C`. Now to this solution , 0.1 M `KMnO_(4)` solution was added till a very faint pink colour persisted.
If instead of `H_(2)SO_(4)`, HCl or `HNO_(3)` of suitable concentration were used, the volume of`KMnO_(4)` soltuionused would have been
A. less in case of HCl but more in case of `HNO_(3)`
B. more in case of HCl but less in case `HNO_(3)`
C. more in both cases
D. less in both case

Answer 1

If HCl were used, the oxygen produced from `KMnO_(4)` will be partly used up for oxidation of HCl. Hence, HCl required will be more. If `HNO_(3)` were used , it itself acts as oxidizing agent and will oxidize the reductant. Hence, `KMnO_(4)` soltuion used will be less.