Assign $A, B, C, D$ from the given type of reaction.
$PbO_2 + HNO_3 \text{ (dil.)} \longrightarrow \text{No reaction}$

$Fe^{3+}$ is reduced to $Fe^{2+}$ by using:
$A$. $H_2O_2$ in presence of $NaOH$
$B$. $Na_2O_2$ in water
$C$. $H_2O_2$ in presence of $H_2SO_4$
$D$. $Na_2O_2$ in presence of $H_2SO_4$

To an acidified dichromate solution,a pinch of $Na_2O_2$ is added and shaken. What is observed?

$H_2S$ ($5$ moles) reacts completely with acidified aqueous potassium permanganate solution. In this reaction,the number of moles of water produced is $x$,and the number of moles of electrons involved is $y$. The value of $(x+y)$ is. . . . . .

Acidified potassium permanganate solution is decolourised by

Assign $A, B, C, D$ from the given type of reaction.
$Ba(NO_3)_2 + Na_2SO_4 \longrightarrow BaSO_4 \downarrow + 2NaNO_3$