Addition of an oxalate solution to an aqueous solution containing a mixture of $Ba^{2+}$,$Sr^{2+}$,and $Ca^{2+}$ ions will precipitate:

The increasing order of reactivity of alkaline earth metals with water is

On heating,which of the following releases $CO_2$ most easily?

Which of the following metals is inert towards reaction with $H_2O$?

How would you explain the following observations?
$(i)$ $BeO$ is almost insoluble but $BeSO_4$ is soluble in water,
$(ii)$ $BaO$ is soluble but $BaSO_4$ is insoluble in water,
$(iii)$ $LiI$ is more soluble than $KI$ in ethanol.

Gypsum $CaSO_4 \cdot 2H_2O$ on heating to about $120\ ^\circ C$ forms a compound which has the chemical composition represented by :-