Sodium metal cannot be stored under

What is the chemical formula for calcium cyanamide?

Which of the following properties is $NOT$ correct for alkali metals?

In the Solvay ammonia process,why does sodium bicarbonate precipitate?

$A$ 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?

Which of the following has the lowest thermal stability?