Molecular weight of $Cu_2S$ is $M$. In the following reaction its equivalent weight is $M / x$. What is $x$?
$Cu_2S + MnO_4^{-} \rightarrow Cu^{2+} + Mn^{2+} + SO_2$

$2 MnO_4^{-} + bI^{-} + cH_2O \rightarrow xI_2 + yMnO_2 + zOH^{-}$
If the above equation is balanced with integer coefficients,the value of $z$ is . . . . . .

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?

What is the charge required to convert $2 \ mol$ of $KMnO_4$ to $MnSO_4$ (in $F$)?

For the redox reaction $MnO_4^- + C_2O_4^{2-} + H^{+} \to Mn^{2+} + CO_2 + H_2O$,the correct coefficients of the reactants for the balanced reaction are:
$MnO_4^-$ : $C_2O_4^{2-}$ : $H^{+}$

Find the values of $x$ and $y$ for the following balanced equation:
$5H_2O_2 + xClO_2 + 2OH^- \to xCl^- + yO_2 + 6H_2O$