Question

Give balanced chemical equations for the following reaction:

Between potassium permanganate and oxalic acid in the presence of dilute sulphuric acid.

Answer 1

It oxidises oxalic acid (or oxalates) to carbon dioxide.

\[\ce{2KMnO4 + 3H2SO4 -> K2SO4 + 2MnSO4 + 3H2O + 5O}\]

\[\begin{array}{cc}
\end{array}\]\[\begin{bmatrix}
\ce{COOH}\phantom{.......................}\\
| \phantom{......}\ce{+ O -> 2CO2 + H2O}\\
\ce{COOH}\phantom{.......................}\\
\end{bmatrix}\] × 5
____________________________________________________________
\[\begin{array}{cc}
\ce{COOH}\phantom{............}\\
\ce{2KMnO4 + 3H2SO4 + 5 \phantom{.}| -> K2SO4 + 2MnSO4 + 8H2O + 10CO2}\\
\ce{\underset{Oxalic acid}{COOH}\phantom{............}}\\
\end{array}\]

Or,

\[\ce{2MnO^-_4 + 16H+ + 5C2O^{2-}_4 -> 2Mn^{2+} + 8H2O + 10CO2}\]