Which of the following alkaline earth metal sulphates has hydration enthalpy higher than the lattice enthalpy?

Solution:

;MgS{O_4}; > ;CaS{O_4}; > ;SrS{O_4}; > ;BaS{O_4}}}">

Hydration energy decreases solubility decreases
Hydration energy $\infty$ solubility
In case of large size anion 

with small charge in cation size there is no considerable change in lattice energy and hence in this case solubility depends on the hydration energy
Hint :
In general in all IA group and IIA group compounds except fluorides and hydroxides solubility down the group decreases
But the two exception are carbonates and bicarbonate of IA group where solubility increases
 

BeSO₄ is highly soluble in water