Explain with resons which of the following half reactions is oxidation and which is reduction?
`Cl_(2)+2e^(-)to2Cl^(-)`

Answer

To determine whether the given half-reaction is an oxidation or reduction process, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Half-Reaction**:
The half-reaction provided is:
\[ \text{Cl}_2 + 2e^- \rightarrow 2\text{Cl}^- \]

2. **Define Oxidation and Reduction**:
- **Oxidation**: This is the process where a species loses electrons. When a substance is oxidized, its oxidation state increases.
- **Reduction**: This is the process where a species gains electrons. When a substance is reduced, its oxidation state decreases.

3. **Analyze the Half-Reaction**:
- In the half-reaction, we see that chlorine gas (\(\text{Cl}_2\)) is gaining 2 electrons (\(2e^-\)) to form two chloride ions (\(2\text{Cl}^-\)).
- The addition of electrons indicates that the chlorine is being reduced.

4. **Determine the Change in Oxidation State**:
- The oxidation state of chlorine in \(\text{Cl}_2\) (elemental form) is 0.
- In the chloride ion (\(\text{Cl}^-\)), the oxidation state of chlorine is -1.
- Since the oxidation state decreases from 0 to -1, this confirms that chlorine is being reduced.

5. **Conclusion**:
- Since \(\text{Cl}_2\) is gaining electrons, the half-reaction is classified as a **reduction reaction**.

### Final Answer:
The half-reaction \(\text{Cl}_2 + 2e^- \rightarrow 2\text{Cl}^-\) is a **reduction reaction** because chlorine is gaining electrons.

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