Which of the following combinations does not liberate $NH_3$ gas?

On reaction of $Lead$ $Sulphide$ with dilute nitric acid,which of the following is not formed?

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.

$NH_4ClO_4 + HNO_3 (\text{dil}) \to HClO_4 + (X) \xrightarrow{\Delta} Y_{(g)}$,$(X)$ and $(Y)$ are respectively

Match the following:

$a$. Pure nitrogen	$i$. Chlorine
$b$. Haber process	$ii$. Sulphuric acid
$c$. Contact process	$iii$. Ammonia
$d$. Deacon's process	$iv$. Sodium azide or Barium azide

Which of the following is the correct option?

How do you account for the reducing behaviour of $H_{3}PO_{2}$ on the basis of its structure?