A `0.56` g sample of limestones is dissolved in acid and the calcium is precipitated as calcium oxalate .The precipitate as calcium oxalate the prepcipate is filtered washed with water and dissolved in dil `H_(2)SO_(4)` The solution required `40ml` of `0.25NKmnO_(4)` solutions for titration .Calculate percentage of `CaO` in limestone sample.
