Calcium cyanamide on treatment with steam produces:

On heating $ZnCl_2 \cdot 2H_2O$,the compound obtained is

Compare the alkali metals and alkaline earth metals with respect to $(i)$ ionization enthalpy,$(ii)$ basicity of oxides,and $(iii)$ solubility of hydroxides.

An aqueous solution of a colourless metal sulphate $M$ gives a white precipitate with $NaOH$. This precipitate is soluble in excess of $NaOH$. On passing $H_2S$ through this solution,a white precipitate is formed. The metal $M$ in the salt is:

Match Column-$I$ with Column-$II$ :

Column-$I$	Column-$II$
$(a)$ $NaOH$	$(p)$ Silvine
$(b)$ $Na_2CO_3$	$(q)$ As cooling agent in nuclear reactor
$(c)$ Liquid $Na$	$(r)$ Detergent soap
$(d)$ Potassium	$(s)$ In purification of Bauxite

$A$ mixture of sodium oxide and calcium oxide is dissolved in water and saturated with excess carbon dioxide gas. The resulting solution is ...... It contains ......... :