Potassium permanganate is prepared from the mineralpyrolusite, MnO_(2). Its crystals have deep purple colour. It acts as an oxidizing agentin the neutral, alkaline as well as acidicmedium. In acidicmedium , it is used in volumetric analysis for estimationof 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 dissolvedin 100mLof distilled water and then 100 mL of 2MH_(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. Th evoluem of KMnO_(4) solution that must have been added to obtain the faint pink colour at the end point must be

Potassium permanganate is prepared from the mineralpyrolusite, MnO_(2)

1.	Potassium permanganate is prepared from the mineralpyrolusite, MnO_(2). Its crystals have deep purple colour. It acts as an oxidizing agentin the neutral, alkaline as well as acidicmedium. In acidicmedium , it is used in volumetric analysis for estimationof 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 dissolvedin 100mLof distilled water and then 100 mL of 2MH_(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. Th evoluem of KMnO_(4) solution that must have been added to obtain the faint pink colour at the end point must be
Answer» 100mL 200 mL 300 mL 400mL SOLUTION :Molesof `( COONa)_(2) = 13.4 // 134 = 0.1` . The BALANCED equation for the reaction INVOLVED is `2MnO_(4)^(-)+ 16 H^(+) + 5CrO_(4)^(2-) rarr 2Mn^(2+) + 8 H_(2)O + 10 CO_(2)` `:. ` Moles of `KMnO_(4)` used `= ( 2)/( 5) xx 0.1= 0.04 ` MOL As`KMnO_(4)` solution used is `0.1 M` , i.e., 0.1 mol are present in 1000 mL, therefore , 0.04mol will be present in 400 mL.