Question

Solubility of an ionic compound in water is mainly dependent on:
a. Lattice enthalpy
b. Hydration enthalpy
Both these factors oppose each other, and the resultant of these factors determines the solubility of an ionic compound in water. If the lattice enthalpy has a larger value, the compound is less soluble. If the hydration enthalpy has larger value, the compound is highly soluble in water.

Which of the following is more soluble in water?

• A. $MgS{O}_4$
• B. $CaS{O}_4$
• C. $SrS{O}_4$
• D. $BaS{O}_4$

Answer 1

The correct option is A $MgS{O}_4$

Among $MgS{O}_4$, $CaS{O}_4$, $SrS{O}_4$ and$BaS{O}_4$, $M{g}^{2+}$ has greater hydration enthalpy which overcomes the lattice enthalpy factor and therefore $MgS{O}_4$ is more soluble.