On heating quick lime with coke in an electric furnace,we get

$A$ metal $M$ reacts with $N_2$ to form a compound $A$ $(M_3N)$. Heating $A$ at high temperature gives back $M$,and passing $A$ through $H_2O$ produces gas $B$. Gas $B$ turns $CuSO_4$ solution into a deep blue color. What are $A$ and $B$?

In the Solvay process,can we obtain sodium carbonate directly by treating the solution containing $(NH_4)_2CO_3$ with sodium chloride? Explain.

Among the following,the number of metals that can be used as electrodes in a photoelectric cell is $.......$ (Integer answer)
$A. Li$
$B. Na$
$C. Rb$
$D. Cs$

Two elements $A$ and $B$ have similar chemical properties. They do not form solid hydrogencarbonates,but react with nitrogen to form nitrides. $A$ and $B,$ respectively,are :

Which of the following oxides will not react with $NaOH$?