Stability of the complex may depend on

Options

A. Ionisation energy
B. Hydration energy
C. Sublimation energy
D. All of these

Answer

### Step-by-Step Solution:

1. **Understanding Complex Stability**: The stability of a complex refers to how well the complex maintains its structure and does not dissociate into its components. This stability can be influenced by various factors.

2. **Factors Affecting Stability**:
- **Ionization Energy**: This is the energy required to remove an electron from an atom or ion. Higher ionization energy can lead to less stability in complexes as it indicates that the metal ion is less willing to lose electrons to form bonds.
- **Hydration Energy**: This is the energy released when ions are surrounded by water molecules. A large amount of hydration energy indicates that the ions are strongly attracted to water, which stabilizes the complex. Therefore, complexes that release a significant amount of hydration energy tend to be more stable.
- **Sublimation Energy**: This is the energy required to convert a solid into a gas. While it can influence the formation of complexes, it is generally less significant compared to hydration energy.

3. **Conclusion on Stability**: Among the factors mentioned, hydration energy plays a crucial role in determining the stability of a complex. A complex that releases a large amount of hydration energy upon formation will be more stable compared to one that does not.

### Final Answer:
The stability of a complex may depend on several factors, including ionization energy, hydration energy, and sublimation energy. However, hydration energy is the most significant factor; a larger hydration energy indicates greater stability of the complex.