Which one is the correct statement with reference to the solubility of `MgSO_4` in water ?

Options

A. `SO_4^(2-)` ions mainly contributes towards hydration energy
B. Sizes of `Mg^(2+)` and `SO_4^(2-)` are similar
C. Hydration energy of `MgSO_4` is higher in comparison to its lattice energy
D. Ionic potential (charge/ radius ratio) of `Mg^(2+)` is very low

Explanation

To determine the correct statement regarding the solubility of \( \text{MgSO}_4 \) in water, we can analyze the factors that influence solubility, specifically hydration energy and lattice energy.

### Step-by-Step Solution:

1. **Understanding Hydration Energy and Lattice Energy**:
- Hydration energy is the energy released when ions are surrounded by water molecules. It is influenced by the size of the ions; smaller ions generally have higher hydration energies because they can attract water molecules more effectively.
- Lattice energy is the energy required to separate one mole of a solid ionic compound into its gaseous ions. It is a measure of the strength of the forces holding the ions together in the solid.

2. **Comparing Hydration Energy and Lattice Energy**:
- For an ionic compound to be soluble in water, the hydration energy must be greater than the lattice energy. This means that the energy released when the ions are hydrated must exceed the energy required to break the ionic bonds in the solid.

3. **Analyzing \( \text{MgSO}_4 \)**:
- In the case of \( \text{MgSO}_4 \), we need to compare its hydration energy with its lattice energy.
- It is known that the hydration energy of \( \text{Mg}^{2+} \) ions is relatively high due to their small size, which leads to strong interactions with water molecules.

4. **Conclusion**:
- Since the hydration energy of \( \text{MgSO}_4 \) is higher than its lattice energy, \( \text{MgSO}_4 \) is soluble in water. Therefore, the correct statement regarding the solubility of \( \text{MgSO}_4 \) is that the hydration energy is greater than the lattice energy.

### Final Answer:
The correct statement with reference to the solubility of \( \text{MgSO}_4 \) in water is that the hydration energy of \( \text{MgSO}_4 \) is higher in comparison to the lattice energy.

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