A metal M readily forms water soluble MSO_(4) water insoluble M(OH)_(2) and oxide MO which becomes inert on heating. The hydroxide is soluble in NaOH. Then M is:

A metal M readily forms water soluble MSO_(4) water insoluble M(OH)_(2

1.	A metal M readily forms water soluble MSO_(4) water insoluble M(OH)_(2) and oxide MO which becomes inert on heating. The hydroxide is soluble in NaOH. Then M is:
Answer» `Be` `Mg` `Ca` `Sr` SOLUTION :Given, `M` reacts to give `MSO_(4)`, which is water SOLUBLE. `M` reacts to give `M (OH)_(2)`, which is water insoluble. `M` reacts to give `MO`, which becomes inert on heating. `M(OH)_(2)` is soluble in `NaOH`, this indicates that `M` is `Be`, since only `Be`, due to its small size and HIGH ionisation enthalpy, is amphoteric and GIVES `M(OH)_(2)` which dissolves in `NaOH`. `Be(OH)_(2)+2NaOHrarrNa_(2)BeO_(2)+2H_(2)O` other facts given are true for `Be` and not for others.