How would you explain the following observations?
(i) BeO is almost insoluble but `BeSo_(4)` is soluble in water
(ii) BaO is soluble but BaSo, is insoluble in water
(iii) Lil is more soluble than KI in ethanol.

Explanation

Lattice energy of BeO is comparatively higher than the hydration energy is almost insoluble in water. Whereas `BeSO_(4)` is ionic in nature and its hydran dominates the lattice energy  the hydration energy
Both BaO and `BaSO_(4)` are ionic compounds but the hydration energy of BaO is higher than utice energy, therefore it is soluble in water
Since the size of `Li^(+)` ion is very small in comparison to `K^(+)` ion, it polarises the electron ud of ion to a great extent. Thus Lil dissolves in ethanol more easily than the kI