Which out of `MgSO_4 or BaSO_4` is more soluble in water?

Explanation

To determine which compound, MgSO₄ or BaSO₄, is more soluble in water, we need to analyze the factors affecting their solubility, particularly the lattice energy and hydration energy.

### Step-by-Step Solution:

1. **Understand Lattice Energy**:
- Lattice energy is the energy released when ions in the gas phase come together to form a solid ionic compound. It is a measure of the strength of the forces between the ions in an ionic solid.
- For both MgSO₄ and BaSO₄, the lattice energy will be different due to the different sizes and charges of the cations (Mg²⁺ and Ba²⁺).

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