For a redox reaction,how many moles of electrons will one mole of $MnO_4^-$ accept in an acidic medium?

Number of moles of $KMnO_4$ required to oxidize one mole of $Fe(C_2O_4)$ in acidic medium is

Write the balanced chemical equation for the following reaction in an acidic medium using the ion-electron method:
Permanganate ion $(MnO_4^-)$ reacts with sulphur dioxide gas to produce $Mn^{+2}$ and hydrogen sulphate ion $(HSO_4^-)$.

In an experiment,$50 \ mL$ of $0.1 \ M$ solution of a metal salt reacted with $25 \ mL$ of $0.1 \ M$ solution of sodium sulphite. The half-equation for the oxidation of sulphite ion is $SO_3^{2-}{(aq)} + H_2O_{(l)} \to SO_4^{2-}{(aq)} + 2H^{+}{(aq)} + 2e^-$. If the oxidation number of the metal in the salt was $3$,what would be the new oxidation number of the metal?

Consider the following equations:
$2 Fe^{2+} + H_2O_2 \rightarrow x A + y B$
(in basic medium)
$2 MnO_4^{-} + 6 H^{+} + 5 H_2O_2 \rightarrow x' C + y' D + z' E$
(in acidic medium)
The sum of the stoichiometric coefficients $x, y, x', y'$ and $z'$ for products $A, B, C, D$ and $E,$ respectively,is............

How many moles of $K_2Cr_2O_7$ can be reduced by $1 \ mol$ of $Sn^{2+}$?