Which of the following compounds are readily soluble in water?

Options

A. `BeSO_(4)`
B. `MgSO_(4)`
C. `BaSO_(4)`
D. `SrSO_(4)`

Explanation

To determine which of the given compounds are readily soluble in water, we need to analyze the solubility of compounds formed by Group 2 elements (alkaline earth metals) based on their lattice energy and hydration energy.

### Step-by-Step Solution:

1. **Identify the Compounds:**
Let's assume the compounds given in the options are:
- A) Beryllium sulfate (BeSO₄)
- B) Magnesium sulfate (MgSO₄)
- C) Strontium sulfate (SrSO₄)
- D) Barium sulfate (BaSO₄)

2. **Understand Lattice Energy and Hydration Energy:**
- **Lattice Energy:** This is the energy required to separate one mole of a solid ionic compound into its gaseous ions. Higher lattice energy means the compound is less soluble.
- **Hydration Energy:** This is the energy released when gaseous ions are surrounded by water molecules. Higher hydration energy means the compound is more soluble.

3. **Analyze Hydration Energy Trends:**
- As we move down the group from beryllium to barium, the size of the cations increases.
- Consequently, the hydration energy decreases because larger cations are less effectively solvated by water molecules.

4. **Compare Hydration Energies:**
- **Beryllium (Be²⁺)** and **Magnesium (Mg²⁺)** have relatively high hydration energies due to their smaller ionic sizes.
- **Strontium (Sr²⁺)** and **Barium (Ba²⁺)** have lower hydration energies because they are larger cations.

5. **Determine Solubility:**
- Since beryllium and magnesium have high hydration energies, they can easily compensate for their lattice energies, making **Beryllium sulfate (BeSO₄)** and **Magnesium sulfate (MgSO₄)** soluble in water.
- On the other hand, strontium and barium have low hydration energies, which do not compensate for their lattice energies, making **Strontium sulfate (SrSO₄)** and **Barium sulfate (BaSO₄)** less soluble or insoluble in water.

6. **Conclusion:**
Based on the analysis, the compounds that are readily soluble in water are:
- **Beryllium sulfate (BeSO₄)**
- **Magnesium sulfate (MgSO₄)**

### Final Answer:
The compounds that are readily soluble in water are **Beryllium sulfate (BeSO₄)** and **Magnesium sulfate (MgSO₄)**.