In the balanced redox reaction $MnO_4^- + xFe^{2+} + yH^+ \rightarrow Mn^{2+} + 5Fe^{3+} + 4H_2O$,what are the values of $x$ and $y$?

$Cr _2 O _7^{2-} \rightarrow Cr ^{3+}_{aq}$
How many moles of $Sn^{2+}$ will be oxidized by $1 \ mol \ Cr_2O_7^{2-}$ into $Sn^{4+}$?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$I_2 + S_2O_3^{2-} \longrightarrow I^{-} + S_4O_6^{2-}$

When $SO_2$ gas is passed through an acidic solution of $K_2Cr_2O_7$,what happens?

$KMnO_4$ acts as an oxidising agent in acidic medium. The number of moles of $KMnO_4$ that will be needed to react with one mole of sulphide ion $(S^{2-})$ in acidic solution is . . . . . . (in $/5$)?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$4FeCr_2O_4 + 8Na_2CO_3 + 7O_2 \longrightarrow 2Fe_2O_3 + 8Na_2CrO_4 + 8CO_2$