Number of moles of $SnCl_2$ required for the reduction of $1$ mole of $K_2Cr_2O_7$ into $Cr^{3+}$ (in acidic medium) is:

Which among the following species acts as a self-indicator?

$KMnO_4$ reacts with $H_2O_2$ in an acidic medium. The number of moles of oxygen produced per mole of $KMnO_4$ is

What is the stoichiometric coefficient of the oxalate ion after balancing the following redox reaction?
$MnO_4^- + C_2O_4^{2-} + H^+ \rightarrow Mn^{2+} + CO_2 + H_2O$

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Pb_3O_4 + 8HCl \xrightarrow{\text{Warm}} 3PbCl_2 + Cl_2 + 4H_2O$

In the balanced reaction $xBrO_3^- + yCr^{3+} + zH_2O \to aBr_2 + bHCrO_4^- + cH^+$,the coefficients $x, y$ and $z$ are