Which of the following elements does not occur in liquid form at room temperature?

Four reactions are given below:
$(i)$ $2Li + 2H_2O \to 2LiOH + H_2$
$(ii)$ $2Na + 2H_2O \to 2NaOH + H_2$
$(iii)$ $2LiNO_3 \xrightarrow{\text{Heat}} 2LiNO_2 + O_2$
$(iv)$ $2NaNO_3 \xrightarrow{\text{Heat}} 2NaNO_2 + O_2$
Which of the above,if any,is wrong?

Which of the following metal carbides is known as a methanide?

Alkali metals are strong reducing agents because

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.

Give points of similarities between lithium and magnesium.