Why does colour of $KMnO_4$ disappear when oxalic acid is added to its solution in acidic medium?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → ${MnO_4}^-$ is reduced to $Mn^{2+}$ which is colourless
- In acidic medium, potassium permanganate (KMnO₄) acts as a strong oxidizing agent.
- When oxalic acid (H₂C₂O₄) is added:
$2MnO_4^- + 5H_2C_2O_4 + 6H^+ \rightarrow 2Mn^{2+} + 10CO_2 + 8H_2O$
- $MnO_4^-$ (purple) is reduced to $Mn^{2+}$ (colourless), causing the disappearance of the purple color.
Hence, the correct option is $MnO_4^-$ is reduced to $Mn^{2+}$ which is colourless.