The element that forms stable compounds in low oxidation state is

In the Ostwald process for the manufacture of $HNO_3$,which of the following is used as a catalyst?

What are the products obtained when ammonia is reacted with excess chlorine?

Excess of ammonia with sodium hypochlorite solution in the presence of glue or gelatine gives:

The electronegativity of a group $13$ element '$E$' is the same as that of $Ge$ (on the Pauling scale and up to one decimal point). The $CORRECT$ statements about $E^{3+}$ are:
$A$. It can act as a reducing agent.
$B$. It can act as an oxidizing agent.
$C$. $E^{3+}$ is more stable than $E^+$.
$D$. The standard electrode potential value for $E^{3+}/E$ is positive.

Give general information about the elements of the $p$-block.