Question

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. What would be $M$ ?

• A. $Be$
• B. $Ba$
• C. $Ca$
• D. $Mg$

Answer 1

Answer: (A)

$Be$

Answer 2

In the periodic table, on moving down, water solubility of alkaline earth metal decreases. Oxides and hydroxides of alkaline earth metal are basic except Be which is amphoteric.