Question

A metal M readily forms water soluble $MS{O}_4$. It also forms oxide MO which becomes inert on heating. Hydroxide $M(OH{)}_2$ is insoluble in water but soluble in NaOH solution. What is M?

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

Answer 1

The correct option is D $Be$

Metal is $Be.$
Be is insoluble in water but soluble in NaOH due to formation of complex.
$Be+2NaOH+2H_{2}O\to N{a}_2\left[Be\right(OH{)}_4]+H_2$