how to calculate the concentration of a standard solution and the concentration of KMnO4 the mass of sodium oxalate used was 0.8367g and then it was diluted down with 50ml water, and 20ml H2SO4 then 25 ml of that solution was diluted down to 250ml with water then 25ml of that was added to a flask and 50ml water was added and 20ml H2SO4. Then 25.90ml of KMnO4 was used to neutralize it the concentration of KMnO4 was 0.01M.