In which of the following, hydration enthalpy is greater than the lattice enthalphy?

Options

A. `BaSO_(4)`
B. `BaCO_(3)`
C. `Na_(2)SO_(4)`
D. `Na_(2)CO_(3)`

Answer

To determine in which of the following compounds the hydration enthalpy is greater than the lattice enthalpy, we need to analyze the solubility of each compound in water. The hydration enthalpy refers to the energy released when ions are surrounded by water molecules, while the lattice enthalpy is the energy required to separate the ions in a solid ionic compound.

### Step-by-Step Solution:

1. **Identify the Compounds**:
We need to evaluate the hydration and lattice enthalpies of the following compounds:
- Barium sulfate (BaSO₄)
- Barium carbonate (BaCO₃)
- Sodium sulfate (Na₂SO₄)
- Sodium carbonate (Na₂CO₃)

2. **Analyze Barium Sulfate (BaSO₄)**:
- Barium sulfate is known to be a white precipitate and is not soluble in water.
- Since it is not soluble, the hydration enthalpy will be less than the lattice enthalpy.

3. **Analyze Barium Carbonate (BaCO₃)**:
- Barium carbonate is also a white precipitate and is not soluble in water.
- Similar to BaSO₄, the hydration enthalpy will be less than the lattice enthalpy.

4. **Analyze Sodium Sulfate (Na₂SO₄)**:
- Sodium sulfate is a strong electrolyte and is soluble in water.
- Because it is soluble, the hydration enthalpy will be greater than the lattice enthalpy.

5. **Analyze Sodium Carbonate (Na₂CO₃)**:
- Sodium carbonate is also soluble in water.
- Thus, the hydration enthalpy will be greater than the lattice enthalpy.

6. **Conclusion**:
- From our analysis, we find that:
- Barium sulfate (BaSO₄) and Barium carbonate (BaCO₃) have hydration enthalpy less than lattice enthalpy.
- Sodium sulfate (Na₂SO₄) and Sodium carbonate (Na₂CO₃) have hydration enthalpy greater than lattice enthalpy.
- Therefore, the correct answer is that hydration enthalpy is greater than lattice enthalpy for sodium sulfate and sodium carbonate.

### Final Answer:
The compounds in which hydration enthalpy is greater than lattice enthalpy are **Sodium sulfate (Na₂SO₄) and Sodium carbonate (Na₂CO₃)**.

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