To which group do the following elements belong? Which of them has the highest metallic character?
$K, Na, Li, Rb$

Sodium metal reacts with $Al_2O_3$ at high temperature to give a sodium compound $X$. Compound $X$ reacts with carbon dioxide in water to give $Y$. What is $Y$?

Identify the correct order of standard enthalpy of formation of sodium halides.

Which of the following,on thermal decomposition,form both acidic and basic oxides along with $O_2$?
$(i)$ $NaNO_3$ $(ii)$ $Ca(NO_3)_2$ $(iii)$ $Be(NO_3)_2$ $(iv)$ $LiNO_3$
The correct option is

$A$ solution of sodium metal in liquid ammonia is a strong reducing agent due to the presence of .........

$A$ metal $X$ on heating in a stream of nitrogen gives $Y$. $Y$ on reaction with ${H_2}O$ gives a colorless gas which,when passed through a $CuSO_4$ solution,gives a blue color. What is $Y$?