Question

Which of the following alkaline earth metal sulphates is least soluble in water?

Options

• BaSO₄

• MgSO₄

• SrSO₄

• CaSO₄

Answer 1

BaSO₄

Explanation:

As the atomic size of the alkaline earth metal sulphates in water increases, so does their solubility, with Be > Mg > Ca > Sr > Ba being the order in which this occurs. In the case of the sulphates of alkaline earth metals, keep in mind that lattice energy remains almost constant as the size of the metal grows; hence, solubility is solely determined by hydration energy.