The number of moles of ${\mathrm{KMnO}}_4$ that will be needed to react completely with one mole of ferrous oxalate in acidic solution is

The number of moles of ${\mathrm{KMnO}}_4$ that will be required for one mole of ferrous oxalate to completely react in an acidic solution is $\frac{3}{5}$.The oxidising agent potassium permanganate is very potent. Both the oxalate ion and the iron(II) ion are oxidised.
Oxidation of oxalate:  $2{\mathrm{MnO}}_4^{-}+16{\mathrm{H}}^{+}+5{\mathrm{C}}_2{\mathrm{O}}_4^{2-}\to 2{\mathrm{Mn}}^{2+}+8{\mathrm{H}}_2\mathrm{O}+10{\mathrm{CO}}_2$
Iron(II) oxidation:          ${\mathrm{MnO}}_4^{-}+8{\mathrm{H}}^{+}+5{\mathrm{Fe}}^{2+}\to {\mathrm{Mn}}^{2+}+4{\mathrm{H}}_2\mathrm{O}+5{\mathrm{Fe}}^{3+}$

Hence, moles of ${\mathrm{KMnO}}_4$ that will be required for one mole of ferrous  oxalate to completely react =  $\frac{3}{5}$ (2 moles for oxalate and 1 mole for iron (II)).