The electrode potential of oxidation half cell

Options

A. a. is independent of the concentration of ions in the cell
B. b. decrease with deccreased concentration of ions is the cell
C. c. decreases with increased concentration of ions in the cell
D. d. none of these.

Answer

To solve the question regarding the electrode potential of an oxidation half-cell, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Electrode Potential**:
- Electrode potential refers to the ability of a half-cell to gain or lose electrons when it is connected to a standard electrode. It is influenced by the concentration of the ions involved in the half-reaction.

2. **Identify the Nernst Equation**:
- The Nernst equation is used to calculate the electrode potential (E) of a cell under non-standard conditions:
\[ E = E^0 - \frac{0.0591}{n} \log \left( \frac{[\text{oxidized form}]}{[\text{reduced form}]} \right) \]
- Here, \(E^0\) is the standard electrode potential, \(n\) is the number of electrons transferred, and the concentrations of the oxidized and reduced forms are used.

3. **Define the Oxidation Half-Cell**:
- In an oxidation half-cell, oxidation occurs, meaning a species loses electrons. For example, a metal M can be oxidized to its ion:
\[ M \rightarrow M^{n+} + n e^- \]

4. **Analyze the Effect of Ion Concentration**:
- In the Nernst equation, if we consider the oxidation of metal M:
\[ E = E^0 - \frac{0.0591}{n} \log \left( \frac{[M^{n+}]}{1} \right) \]
- Since the concentration of solid M is taken as 1, the equation simplifies to:
\[ E = E^0 - \frac{0.0591}{n} \log \left( [M^{n+}] \right) \]

5. **Determine the Relationship Between Concentration and Electrode Potential**:
- If the concentration of the oxidized form (M^{n+}) increases, the logarithmic term increases, leading to a decrease in the electrode potential (E). Thus, as the concentration of ions in the cell increases, the electrode potential decreases.

6. **Select the Correct Option**:
- Based on the analysis, the correct answer is:
- **C: Decreases with increased concentration of ions in the cell**.