How much will the reduction potential of a hydrogen electrode change when its solution initially at `pH=0` is neutralized to `pH=7` ?

Options

A. Increase by 0.059 V
B. Decrease by 0.059 V
C. Increase by 0.41 V
D. Decrease by 0.41 V

Answer

To determine how much the reduction potential of a hydrogen electrode changes when its solution is neutralized from pH 0 to pH 7, we can follow these steps:

### Step 1: Understand the relationship between pH and reduction potential
The reduction potential (E) of the hydrogen electrode can be calculated using the formula:
\[ E = -0.059 \times \text{pH} \]
This formula indicates that the reduction potential is directly related to the pH of the solution.

### Step 2: Calculate the reduction potential at pH 0
When the pH is 0:
\[ E_{pH=0} = -0.059 \times 0 = 0 \, \text{V} \]

### Step 3: Calculate the reduction potential at pH 7
Now, when the pH is changed to 7:
\[ E_{pH=7} = -0.059 \times 7 = -0.413 \, \text{V} \]
(For simplicity, we can round this to -0.41 V)

### Step 4: Determine the change in reduction potential
To find the change in reduction potential (ΔE), we subtract the initial potential from the final potential:
\[ \Delta E = E_{pH=7} - E_{pH=0} \]
\[ \Delta E = -0.41 \, \text{V} - 0 \, \text{V} = -0.41 \, \text{V} \]

### Step 5: Conclusion
The reduction potential of the hydrogen electrode decreases by 0.41 V when the solution is neutralized from pH 0 to pH 7.

### Final Answer
The reduction potential decreases by 0.41 V.

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