How many isotopes of nitrogen gas are stable? Which are they?

Under which conditions can active nitrogen be obtained from $N_2$ gas using an electric spark?

In the following reaction,identify the nature of the products formed by the complete hydrolysis of $\underline{P}_4O_8$ at $R.T$:
$\underline{P}_4O_8 + H_2O \longrightarrow H_3PO_3 + H_3PO_4$

$8 NH_{3} + 3 Cl_{2} \rightarrow X$ (Excess $NH_{3}$)
$NH_{3} + 3 Cl_{2} \rightarrow Y$ (Excess $Cl_{2}$)
What are $X$ and $Y$ in the above reactions?

Identify the false statement about red phosphorus.

Regarding the hydrides of group $15$ elements $EH_{3}$ $(E = N, P, As, Sb, Bi)$, select the correct statement from the following:
$A$. The stability of hydrides decreases down the group.
$B$. The basicity of hydrides decreases down the group.
$C$. The reducing character increases down the group.
$D$. The boiling point increases down the group.
Choose the correct answer from the options given below: