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

$N_2$ forms $NCl_3$,whereas $P$ can form both $PCl_3$ and $PCl_5$. Why?

Give reasons: Concentrated $HNO_3$ can be transported in aluminium containers.

Cyclic polymetaphosphates have the general formula of $[P_nO_{3n}]^{n-}$. Cyclic trimeric polymetaphosphate $(P_3O_9)^{3-}$ has commercial importance. Which of the following is not true regarding $P_3O_9^{3-}$?

Match $List-I$ with $List-II$,match the gas evolved during each reaction.

$List-I$	$List-II$
$A$. $(NH_4)_2Cr_2O_7 \xrightarrow{\Delta}$	$I$. $H_2$
$B$. $KMnO_4 + HCl \rightarrow$	$II$. $N_2$
$C$. $Al + NaOH + H_2O \rightarrow$	$III$. $O_2$
$D$. $NaNO_3 \xrightarrow{\Delta}$	$IV$. $Cl_2$

Choose the correct answer from the options given below.

First ionisation enthalpy values of first four group $15$ elements are given below. Choose the correct value for the element that is a main component of apatite family $:$