$A$ metal $M$ reacts with $N_2$ to form a compound $A$ $(M_3N)$. Heating $A$ at a high temperature gives back $M$,and passing $A$ through $H_2O$ results in the evolution of gas $B$. Gas $B$ turns $CuSO_4$ solution blue. What are $A$ and $B$ respectively?

The frequency of the radiation emitted by alkali metals in the flame test follows the order:

Comment on each of the following observations:
$(a)$ The mobilities of the alkali metal ions in aqueous solution are
$Li^{+} < Na^{+} < K^{+} < Rb^{+} < Cs^{+}$
$(b)$ Lithium is the only alkali metal to form a nitride directly.
$(c)$ $E^{\circ}$ for $M^{2+}_{(aq)} + 2e^{-} \longrightarrow M_{(s)}$ (where $M = Ca, Sr$ or $Ba$) is nearly constant.

Which gas/gases evolve$(s)$ when sodium metal is reacted with water at room temperature?

Match the following:

Compound	Uses
$1$. Soda ash	$a$. In purification of sugar
$2$. Calcium oxide	$b$. As an antacid
$3$. Baking soda	$c$. In paper and textile industries
	$d$. To prepare pure fats and oils

Choose the false statement regarding the properties of sodium hydroxide $(NaOH)$.