In a standard hydrogen electrode, the concentration of `H^+` is

Options

A. 0.1 M
B. 1 M
C. 10 M
D. Not fixed

Answer

To determine the concentration of \( H^+ \) in a standard hydrogen electrode (SHE), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Standard Hydrogen Electrode (SHE)**:
- The SHE is a reference electrode used in electrochemistry.
- It consists of a platinum electrode in contact with a solution containing hydrogen ions (\( H^+ \)) and hydrogen gas (\( H_2 \)) at a specific pressure.

2. **Conditions of the SHE**:
- The pressure of hydrogen gas (\( H_2 \)) is maintained at 1 atmosphere (1 atm).
- The concentration of hydrogen ions (\( H^+ \)) in the solution is maintained at a specific value.
- The temperature is typically maintained at 298 Kelvin (25 degrees Celsius).

3. **Concentration of \( H^+ \)**:
- In a standard hydrogen electrode, the concentration of \( H^+ \) ions is defined to be 1 molar (1 M).
- This is a standard condition for the SHE, which allows for consistent measurements and comparisons with other electrodes.

4. **Conclusion**:
- Therefore, the concentration of \( H^+ \) in a standard hydrogen electrode is 1 M.

### Final Answer:
The concentration of \( H^+ \) in a standard hydrogen electrode is **1 M**.

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