Which of the following compounds are readily soluble in water?

a.  ${\mathrm{BeSO}}_{4}$

b.  ${\mathrm{MgSO}}_{4}$

c.  ${\mathrm{BaSO}}_{4}$

d.  ${\mathrm{SrSO}}_{4}$

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

Solubility of sulphates of alkaline earth metals in water decreases from Be to $\mathrm{Ba}·{\mathrm{BeSO}}_{4}$ are fairly soluble while ${\mathrm{BaSO}}_{4}$ is almost completely insoluble.
The decreasing solubility of ${\mathrm{BeSO}}_{4}$ to ${\mathrm{BaSO}}_{4}$ can be explained on the basis of decreasing hydration energy from Be2+ to Ba2+ (as size increases). For BeSO4 and MgSO4, hydration energy is more than lattice energy and so they are readily soluble.