Question

Which is most easily soluble in water
MgSO4
CaSO4
BaSO4
Srso4​

Answer 1

• The hydration enthalpies of BeSO4 and MgSO4 are quite high because of small size of Be2+ and Mg2+ ions.
• These hydration enthalpy values are higher than their corresponding lattice enthalpies and therefore, BeSO4 and MgSO4 are highly soluble in water.
• However, hydration enthalpies of CaSO4, SrSO4 and BaSO4 are not very high as compared to their respective lattice enthalpies and hence these are insoluble in water.