Consider this reaction `Fe^( + + ) undersetlarr to Fe^( + + +) + e^-`

Options

A. The reaction toward the left is a reduction
B. The reaction toward the right is a reduction
C. The reaction toward the right is an oxidation.
D. One and three are correct

Explanation

To solve the given reaction \( \text{Fe}^{2+} \rightleftharpoons \text{Fe}^{3+} + e^- \), we can analyze the oxidation and reduction processes involved.

### Step-by-Step Solution:

1. **Identify the Species Involved**:
- We have two iron species: \( \text{Fe}^{2+} \) and \( \text{Fe}^{3+} \).
- An electron \( e^- \) is also involved in the reaction.

2. **Determine the Change in Oxidation State**:
- The oxidation state of iron in \( \text{Fe}^{2+} \) is +2.
- The oxidation state of iron in \( \text{Fe}^{3+} \) is +3.
- This indicates that iron is losing an electron to go from +2 to +3.

3. **Identify the Type of Reaction**:
- Since \( \text{Fe}^{2+} \) is losing an electron, this process is called oxidation.
- The half-reaction can be written as:
\[ \text{Fe}^{2+} \rightarrow \text{Fe}^{3+} + e^- \]
- This shows that \( \text{Fe}^{2+} \) is oxidized to \( \text{Fe}^{3+} \).

4. **Identify the Reverse Reaction**:
- The reverse reaction would involve the gain of an electron by \( \text{Fe}^{3+} \):
\[ \text{Fe}^{3+} + e^- \rightarrow \text{Fe}^{2+} \]
- This process is called reduction because \( \text{Fe}^{3+} \) is gaining an electron.

5. **Conclusion**:
- In the forward direction, \( \text{Fe}^{2+} \) is oxidized to \( \text{Fe}^{3+} \) (loss of electron).
- In the reverse direction, \( \text{Fe}^{3+} \) is reduced to \( \text{Fe}^{2+} \) (gain of electron).

### Final Answer:
- The reaction \( \text{Fe}^{2+} \rightleftharpoons \text{Fe}^{3+} + e^- \) involves oxidation of \( \text{Fe}^{2+} \) to \( \text{Fe}^{3+} \) and reduction of \( \text{Fe}^{3+} \) to \( \text{Fe}^{2+} \).