Question

Hydration energy of :

• A. $B{e}^{2+}>N{a}^{+}$
• B. $B{e}^{2+}<N{a}^{+}$
• C. $B{e}^{2+}=N{a}^{+}$
• D. None of these

Answer 1

The correct option is A $B{e}^{2+}>N{a}^{+}$

The heat energy released when new bonds are made between the ions and water moleculesis known as the hydration enthalpy of the ion. The hydration enthalpy is the enthalpy change when 1 mole of gaseous ions dissolve in sufficient water to give an infinitely dilute solution. Hydration enthalpies are always negative. Larger the atomic size lesser the hydration energy or the energy decreases.
The size of $N{a}^{+}$ greater than $B{e}^{2+}$ So the hydration energy of $B{e}^{2+}$ is greater than $N{a}^{+}$.
So the correct oreder of hydration energy is $B{e}^{2+}>N{a}^{+}$
Hence option A is correct.