How many moles of acidic $KMnO_4$ are required to oxidize $1$ mole of ferrous oxalate $(FeC_2O_4)$?

$50 \ mL$ of $0.1 \ M$ solution of a salt reacted with $25 \ mL$ of $0.1 \ M$ solution of sodium sulphite. The half-reaction for the oxidation of sulphite ion is:
$SO_{3}^{2-} (aq) + H_{2}O (l) \to SO_{4}^{2-} (aq) + 2H^{+} (aq) + 2e^{-}$
If the oxidation number of the metal in the salt was $+3$,what would be the new oxidation number of the metal?

Ferrous sulphate on strong heating gives:

$H_2O_2$ with $KMnO_4$ in acidic medium gives a manganese compound '$X$' and in basic medium gives another manganese compound '$Y$'. The oxidation state of manganese in $X$ and $Y$,respectively are

The number of moles of $KMnO_4$ reduced by $1 \ mol$ of $KI$ in basic medium is .............

Which of the following reactions is a decomposition redox reaction?