Acidified potassium dichromate on reacting with a sulphite is reduced to

Which of the following metal nitrate produces a gaseous product when it reacts with a $KCN$ solution?

$KMnO_4$ reacts in alkaline medium as follows:
$2KMnO_4 + 2KOH \to 2K_2MnO_4 + H_2O + O$
What is the equivalent weight of $KMnO_4$?
(Atomic weights: $K = 39, Mn = 55, O = 16$)

In dilute alkaline solution,$MnO_4^-$ changes to:

Consider the following equations:
$2 Fe^{2+} + H_2O_2 \rightarrow x A + y B$
(in basic medium)
$2 MnO_4^{-} + 6 H^{+} + 5 H_2O_2 \rightarrow x' C + y' D + z' E$
(in acidic medium)
The sum of the stoichiometric coefficients $x, y, x', y'$ and $z'$ for products $A, B, C, D$ and $E,$ respectively,is............

For the reaction $3K_2MnO_4 + 2H_2SO_4 \rightarrow 2KMnO_4 + K_2SO_4 + MnO_2 + 2H_2O$,what is the stoichiometric ratio of the reactants $K_2MnO_4$ to $H_2SO_4$?