What is the product obtained when one mole of magnesium nitride is reacted with excess water?

Match the following columns:

Column-$I$	Column-$II$
$(i)$ Solvay process	$(p)$ $Na_2O$
$(ii)$ Evolve $CO_2$ on heating	$(q)$ $Na_2O_2$
$(iii)$ Aqueous solution is not neutral towards litmus	$(r)$ $NaHCO_3$
$(iv)$ Used as air purifier in submarine	$(s)$ $Na_2CO_3$

Copper is very slowly oxidized on the surface in moist air,giving a green coating of verdigris. The chemical formula of verdigris is:

The two major constituents of Portland cement are

The pair$(s)$ of reagents that yield paramagnetic species is/are:
$A$. $Na$ and excess of $NH_3$
$B$. $K$ and excess of $O_2$
$C$. $Cu$ and dilute $HNO_3$
$D$. $O_2$ and $2-ethylanthraquinol$

The correct statements among the following are:
$(A)$ $BeH_2$ and $MgH_2$ are polymeric in nature.
$(B)$ $LiH$ is unreactive to oxygen at moderate temperatures.
$(C)$ $BeH_2$ and $MgH_2$ possess significant covalent character.
$(D)$ The stability of alkali metal hydrides follows the order $LiH < NaH < KH < RbH < CsH$.