The hydration energy of `Mg^(2+)` is larger than that of

Options

A. `Al^(3+)`
B. `Na^+`
C. `Be^(2+)`
D. `K^+`

Answer

To solve the question regarding the hydration energy of \( \text{Mg}^{2+} \), we need to understand the concept of hydration energy and how it relates to the size and charge of ions.

### Step-by-Step Solution:

1. **Understanding Hydration Energy**:
Hydration energy is the energy released when one mole of an ion is surrounded by water molecules. It is influenced by the charge and size of the ion. Higher charge and smaller size typically lead to higher hydration energy.

2. **Comparing Ions**:
We need to compare the hydration energy of \( \text{Mg}^{2+} \) with other ions. The ions we will consider based on the options provided are \( \text{K}^{+} \), \( \text{Na}^{+} \), \( \text{Be}^{2+} \), and \( \text{Al}^{3+} \).

3. **Charge and Size Relationship**:
- \( \text{K}^{+} \) has a charge of +1 and is larger in size.
- \( \text{Na}^{+} \) has a charge of +1 and is smaller than \( \text{K}^{+} \).
- \( \text{Mg}^{2+} \) has a charge of +2 and is smaller than both \( \text{Na}^{+} \) and \( \text{K}^{+} \).
- \( \text{Be}^{2+} \) has a charge of +2 and is smaller than \( \text{Mg}^{2+} \).
- \( \text{Al}^{3+} \) has a charge of +3 and is smaller than \( \text{Be}^{2+} \).

4. **Hydration Energy Order**:
The order of hydration energy generally increases with increasing charge and decreasing size. Thus, we can establish the following order:
- \( \text{Al}^{3+} > \text{Be}^{2+} > \text{Mg}^{2+} > \text{Na}^{+} > \text{K}^{+} \)

5. **Conclusion**:
From the order established, we can conclude that the hydration energy of \( \text{Mg}^{2+} \) is larger than that of \( \text{Na}^{+} \) and \( \text{K}^{+} \). Therefore, the answer to the question is that the hydration energy of \( \text{Mg}^{2+} \) is larger than that of both \( \text{Na}^{+} \) and \( \text{K}^{+} \).

### Final Answer:
The hydration energy of \( \text{Mg}^{2+} \) is larger than that of \( \text{Na}^{+} \) and \( \text{K}^{+} \).