Which of the following can not be calculated by Born Haber cycle formation of MgO :-

Options

A. Lattice energy of MgO
B. EA of oxygen
C. Hydration energy of `Mg^(+2)`
D. I.E. of Mg

Explanation

To determine which quantity cannot be calculated by the Born-Haber cycle for the formation of MgO, we need to analyze the steps involved in the Born-Haber cycle and the quantities that can be derived from it.

### Step-by-Step Solution:

1. **Understand the Born-Haber Cycle**:
The Born-Haber cycle is a thermodynamic cycle that relates the lattice energy of an ionic compound to its formation from its constituent elements. It involves several steps, including sublimation, ionization, dissociation, electron gain, and combination of ions.

2. **Identify the Steps in the Formation of MgO**:
- **Sublimation**: Convert solid magnesium (Mg) to gaseous magnesium (Mg(g)).
- **Ionization**: Convert gaseous magnesium (Mg(g)) to magnesium ions (Mg²⁺).
- **Dissociation**: Convert molecular oxygen (O₂) to atomic oxygen (O(g)).
- **Electron Gain**: Convert atomic oxygen (O(g)) to oxide ions (O²⁻).
- **Combination**: Combine Mg²⁺ and O²⁻ to form solid MgO.

3. **Quantities Calculated by the Born-Haber Cycle**:
- **Lattice Energy of MgO**: This is calculated from the energy changes involved in the formation of MgO from its gaseous ions.
- **Ionization Energy of Magnesium**: This is the energy required to ionize gaseous magnesium into Mg²⁺.
- **Electron Affinity of Oxygen**: This is the energy change when atomic oxygen gains an electron to form O²⁻.

4. **Identify the Quantity Not Calculated**:
- **Hydration Energy of MgO**: This is the energy released when MgO dissolves in water and forms hydrated ions. It is not part of the Born-Haber cycle, which focuses on the formation of the solid from its gaseous ions.

5. **Conclusion**:
The quantity that cannot be calculated by the Born-Haber cycle for the formation of MgO is the **hydration energy of MgO**.

### Final Answer:
**C. Hydration energy of MgO** cannot be calculated using the Born-Haber cycle.