Question

$BeO$ is almost insoluble but $BeS{O}_4$ is soluble in water. Explain.

Answer 1

$BeO$ is almost insoluble in water and ${BeSO}_4$ is soluble in water because ${Be}^{2+}$ is a small cation with high polarising power and $O^{2-}$ is a small anion. When BeO is dissolved in water, the hydration energy of its ions is not sufficient to overcome the high lattice energy. Thus, $BeO$ is insoluble in water