Oxidation involves

Options

A. Loss of electron
B. Gain of electron
C. Increase in valency of negative part
D. All

Answer

To solve the question "Oxidation involves," we need to analyze the options provided and understand the concept of oxidation in redox reactions.

### Step-by-Step Solution:

1. **Understanding Oxidation**:
- Oxidation is a chemical process that involves the loss of electrons by a substance. This can also be associated with an increase in oxidation state.

2. **Analyzing the Options**:
- **Option A: Loss of electron**: This is a fundamental definition of oxidation. When a substance loses electrons, it is oxidized.
- **Option B: Gain of electron**: This is incorrect. Gaining electrons is defined as reduction, not oxidation.
- **Option C: Increase in valency of negative part**: Oxidation typically involves an increase in oxidation state, but this option is misleading because it refers to the negative part (anions) which usually decrease in valency when they gain electrons. Therefore, this is incorrect.
- **Option D: All of the above**: Since options B and C are incorrect, this option cannot be correct.

3. **Conclusion**:
- Based on the analysis, the correct answer is **Option A: Loss of electron**.

### Final Answer:
**Oxidation involves the loss of electrons (Option A).**

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