Question

Amongst the following hydroxide, the one which has the lowest value of solubility product $\left(\right.K_{s p}\left.\right)$ at ordinary temperature (about $25^\circ C$ ) is

• A. $Mg\left(\right.OH\left(\left.\right)_{2}$
• B. $Ca\left(\right.OH\left(\left.\right)_{2}$
• C. $Sr\left(\right.OH\left(\left.\right)_{2}$
• D. $Be\left(\right.OH\left(\left.\right)_{2}$

Answer 1

Answer: (D)

The solubility of hydroxides of group 2 elements increases on moving down the group. $Be\left(\right.OH\left(\left.\right)_{2}$ has minimum solubility in water. The lesser the solubility of the hydroxides, the smaller will be is solubility product. Hence, $Be\left(\right.OH\left(\left.\right)_{2}$ has the lowest solubility product amongst the group 2 hydroxides.