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_(4)` is insoluble in water
(iii) LiI is more soluble than KI in ethanol

Explanation

`Li^(+)` ions are much smaller than `K^(+)` ions and can polarise `I^(-)` ions to a greater extent than `K^(+)` ions. Thus, Lil is more covalent than Kl. This is why Lil is more soluble in ethanol (an organic solvent) than Kl.