Why does the solubility of alkaline earth metal hydroxides in water increase down the group?

Explanation

Among alkaline earth metal hydroxides, the anion, i.e., OH. ion is common, therefore, the lattice enthalpy depends upon the size of the cation. Since the lattice enthalpy decrease much more than the hydration enthalpy with increasing ionic size, the solubility of the metal hydroxides increases as we move down the group.