Gypsum $CaSO_4 \cdot 2H_2O$ on heating to about $120 \, ^oC$ forms a compound which has the chemical composition represented by

Statement $A$: Calcium chloride $(CaCl_2)$ is not useful for drying alcohols or $NH_3$.
Reason $R$: $CaCl_2$ is not a good desiccant.

$A$ compound $x$ on heating gives a colourless gas. The residue is dissolved in water to obtain $y$. Excess $CO_2$ is bubbled through the aqueous solution of $y$ and $z$ is formed. $z$ on gentle heating gives back $x$. The compound $x$ is:

Identify the alkaline earth metal from the following.

Which of the following is the weakest base among $NaOH$,$Ca(OH)_2$,$KOH$,and $Ba(OH)_2$?

Consider the following statements:
Statement-$I$: Both $BeSO_4$ and $MgSO_4$ are readily soluble in water.
Statement-$II$: Among the nitrates of alkaline earth metals,only $Be(NO_3)_2$ on strong heating gives its oxide,$NO_2$,and $O_2$.