Solubility depends on the lattice energy of the solid and the hydration energy of the ions. Some lattice values for Group - II compounds are much lighter than the values for Group - I compounds, because of the effect of the increased charge on the ions in the Boron - Lande equation. Taking any one particular negative ion the lattice energy decreases as the size of the metal increases. The hydration energy also decreases as the metal ions become larger. For a substance to dissolve, the hydration energy must exceed thelattice energy
The correct order of hydration energies is

Options

A. `Be^(2+)ltCa^(2+)ltCr^(2+)ltBa^(2+)`
B. `Be^(2+)ltSr^(2+)ltCa^(2+)ltBa^(2+)`
C. `Be^(2+)gtSr^(2+)gtCa^(2+)gtBa^(2+)`
D. `Be^(2+)gtCa^(2+)gtSr^(2+)gtBa^(2+)`

Answer

D

Explanation

The order of hydration energies `Be^(+2) gt Ca^(+2)gt Sr^(+2) gt Ba^(+2)`
The hydration energy depends on size of the ion, lesser the size higher will be the hydration energy