Which of the following alkaline earth metal sulphates has hydration enthalpy higher than the lattice enthalpy?
(a) CaSO4 (b) BeSO4
(c) BaSO4 (d) SrSO4
(b) Key Idea Hydration energy varies inversely with size and in sulphates of alkaline earth metals lattice energy remains almost constant.
The order of size of alkaline earth metals is
Thus, the order of hydration energy is
Hence, BeSO4 has the hydration enthalpy higher than the lattice enthalpy.