$A$ metal $M$ readily forms its sulphate $MSO_4$ which is water-soluble. It forms its oxide $MO$ which becomes inert on heating. It forms its insoluble hydroxide $M(OH)_2$ which is soluble in $NaOH$ solution. Then $M$ is

The hydroxides which sublime on heating are

What are $X$,$Y$ and $Z$ in the following reactions?
$CaCO_3 \stackrel{\Delta}{\rightleftharpoons} CO_2 + X$
$X + H_2O \longrightarrow Y$
$Y + Cl_2 \longrightarrow Z$

Beryllium resembles much with

The compound $A$ on heating gives a colourless gas and a residue that is dissolved in water to obtain $B$. Excess of $CO_2$ is bubbled through aqueous solution of $B$,$C$ is formed which is recovered in the solid form. Solid $C$ on gentle heating gives back $A$. The compound $A$ is:

Among the sulphates of alkaline earth metals,the solubilities of $BeSO_4$ and $MgSO_4$ in water,respectively,are