A solution of potassium permanganate (KMnO4) is dark purple. An oxalic acid, H2C2O4 which is having 0.5000 g dissolved in about 250 ml of 0.5M H2SO4. When that solution is slowly mixed to oxalic acid the purple color disappears, because the products given below are essentially colorless.
Unbalanced equation
H2C2O4 (aq) + MnO4- (aq) = CO2 (g) + Mn+2 (aq)
Determine the concentration of the permanganate solution when adding just one drop beyond 43.47 ml of the permanganate solution to the oxalate solution, the solution turns light purple.
Balanced equation
5H2C02O4 + 2MnO4 {-} + 6H {+} = 10CO2 + 2Mn {2+} + 8H2O