The standard electrode potential of `M^(+) /M` in aqueous solution does not depend on

Options

A. Hydration of a gaseous metal ion
B. Sublimation of a solid metal
C. Ionisation of a solid metal atom
D. Ionisation of a gaseous metal atom

Answer

To determine what the standard electrode potential of \( M^+/M \) in an aqueous solution does not depend on, we can analyze the given options one by one.

### Step-by-Step Solution:

1. **Understanding Standard Electrode Potential**:
The standard electrode potential (\( E^\circ \)) of a half-cell reaction is influenced by various factors including the state of the metal, the ionization energy, and the hydration energy of the ions involved.

2. **Analyzing the Options**:
- **Option 1: Hydration of a gaseous metal ion**:
The hydration energy of a gaseous metal ion is a significant factor that affects the standard electrode potential. When a metal ion is hydrated, it releases energy that influences the potential. Therefore, this option is **not the answer**.

- **Option 2: Sublimation of a solid metal**:
The sublimation of a solid metal into a gaseous state is also relevant because it involves energy changes that affect the formation of ions from the solid metal. Hence, this option is **not the answer**.

- **Option 3: Ionization of a solid metal atom**:
This option is crucial. The ionization of a solid metal atom cannot occur directly in the solid state; it must be in the gaseous state or in solution. Therefore, the standard electrode potential does not depend on the ionization of a solid metal atom. This option is **the correct answer**.

- **Option 4: Ionization of gaseous metal**:
The ionization of a gaseous metal is relevant because it directly affects the formation of the metal ion from the gaseous metal. Thus, this option is **not the answer**.

3. **Conclusion**:
Based on the analysis, the standard electrode potential of \( M^+/M \) in aqueous solution does not depend on the ionization of a solid metal atom. Therefore, the correct answer is **Option 3**.