The measured potential for, `Mg^(2+) + 2e^(-) hArr Mg (s)` does not depend upon:

Options

A. Raising the temperature
B. Increasing the concentration of `Mg^(2+)` ion
C. Making the magnesium plate bigger
D. Decreasing the concentration of `Mg^(2+)` ion

Answer

To solve the question regarding the measured potential for the reaction \( \text{Mg}^{2+} + 2e^- \rightleftharpoons \text{Mg (s)} \), we need to analyze how various factors affect the measured potential of this electrochemical reaction.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
The reaction involves the reduction of magnesium ions (\( \text{Mg}^{2+} \)) to solid magnesium (\( \text{Mg (s)} \)). The measured potential of this reaction is influenced by several factors.

2. **Factors Influencing Measured Potential**:
- **Temperature**: The measured potential can change with temperature due to changes in kinetic energy and reaction rates.
- **Concentration of \( \text{Mg}^{2+} \)**: According to the Nernst equation, the potential is affected by the concentration of the ions involved in the reaction. Increasing or decreasing the concentration of \( \text{Mg}^{2+} \) will affect the measured potential.
- **Size of Magnesium Plate**: The size of the magnesium plate (the solid form) does not affect the potential because the solid magnesium is not involved in the reaction dynamics. The reaction only depends on the concentration of ions in solution and the electrons involved in the reduction process.
- **Decreasing Concentration of \( \text{Mg}^{2+} \)**: Similar to increasing concentration, decreasing the concentration of \( \text{Mg}^{2+} \) will also affect the measured potential.

3. **Conclusion**:
Among the options provided, the size of the magnesium plate does not influence the measured potential of the reaction. Therefore, the correct answer is that the measured potential does not depend upon the size of the magnesium plate.

### Final Answer:
The measured potential for \( \text{Mg}^{2+} + 2e^- \rightleftharpoons \text{Mg (s)} \) does not depend upon the size of the magnesium plate.

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