Number of moles of ${{\mathrm{MnO}}_4}^{-}$ required to oxidize one mole of ferrous oxalate completely in acidic medium will be:

For the redox reaction, ${\mathrm{MnO}}_4^{-}+{\mathrm{C}}_2{\mathrm{O}}_4^{2-}+{\mathrm{H}}^{+}⟶{\mathrm{Mn}}^{2+}+{\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O}$

The correct coefficients of reactants in the balanced equation are:

In view of the signs of ${\mathrm{\Delta }}_{\mathrm{r}}\mathrm{G}°$ for the following reactions: 

${\mathrm{PbO}}_2+\mathrm{Pb}\to 2\mathrm{PbO}$, ${\mathrm{\Delta }}_{\mathrm{r}}\mathrm{G}°<0$

${\mathrm{SnO}}_2+\mathrm{Sn}\to 2\mathrm{SnO}$, ${\mathrm{\Delta }}_{\mathrm{r}}\mathrm{G}°>0$

which oxidation states are more characteristics for lead and tin?