Amphoteric hydroxide react with both alkalies and acids. Which of the following group 2 metal hydroxides is soluble in sodium hydroxide?

The solubility of hydroxides of alkaline earth metals increases from Be to Ba, in water. Be(OH)₂ and Mg(OH)₂ are almost insoluble. Due to high hydration enthalpy and high Iattice energy Be(OH)₂ is not soluble in water.
Be(OH), is an amphoteric hydroxide. With acids, Be(OH), is neutralised giving salts.

$\mathrm{Be}(\mathrm{OH}{)}_2+2\mathrm{HCl}⟶{\mathrm{BeCl}}_2+2{\mathrm{H}}_2\mathrm{O}$

Be(OH)₂ reacts with NaOH also forming beryIlate.

$\mathrm{Be}(\mathrm{OH}{)}_2+2\mathrm{NaOH}⟶{\mathrm{Na}}_2{\mathrm{BeO}}_2+2{\mathrm{H}}_2\mathrm{O}$