Question

$Be{F}_2$ is soluble in water whereas, the fluorides of other alkaline earth metals are insoluble. This is because of the:

• A. Ionic nature of $Be{F}_2$
• B. Greater hydration energy of $B{e}^{2+}$ ion as compared to the lattice energy
• C. Covalent nature of $Be{F}_2$
• D. None of these

Answer 1

The correct option is B Greater hydration energy of $B{e}^{2+}$ ion as compared to the lattice energy

Greater the hydration energy, greater is the solubility.
Fluorides of alkaline earth metals except $Be{F}_2$ are insoluble in water. The solubility of $Be{F}_2$ in water is due to the higher hydration energy on account of the smaller size of $B{e}^{2+}$ ion and $F^{-}$ ion and the high charge density of $B{e}^{2+}$ ion.