How much potassium permanganate is needed to completely oxidize ferrous oxalate?
See here.

The "green salt" is $\ce{K3Fe(C2O4)3.3 H2O}$.
\begin{align}
\ce{MnO4- + 8H+ +5e- &amp;-&gt; Mn^2+ + 4 H2O}\\
\ce{C2O4^2- &amp;-&gt; 2 CO2 + 2e-}\\
\ce{2 MnO4^- + 16 H+ + 5 C2O4^2- &amp;-&gt; 2 Mn^2+ + 8 H2O + 10 CO2 (g)}\\
\end{align}

One expects all the oxalate is oxidized to $\ce{CO2}$ and $\ce{Fe(II)}$ is oxidized to $\ce{Fe(III)}$.