The correct order of decomposition temperature of $MgCO_3$ $(X)$,$BaCO_3$ $(Y)$,$CaCO_3$ $(Z)$ is

Predict the feasibility of the given reactions in aqueous solution:
$(i)$ $Be(OH)_2 + 2 OH^{-} \longrightarrow [Be(OH)_4]^{2-}$
$(ii)$ $Be(OH)_2 + 2 H^{+} \longrightarrow Be^{2+} + 2 H_2O$

The correct order of thermal stability of hydroxides is

Which of the following is least thermally stable?

From which of the following is the hydration energy of $Mg^{2+}$ larger?

What is the chemical formula of Plaster of Paris?