Question:
Explain why the colour of KMnO4 disappears when oxalic acid is added to its solution in acidic medium.
Solution:
This is a redox titration. The deep purple colour of KMnO4 disappears due to the formation of MnSO4.
5H2C2O4 + 2KMnO4 +3H2SO4 ——>2MnSO4 + 8H2O + K2SO4 +10CO2