Oxidation and reduction take place in a cell, then its electromotive force will be

Options

A. Positive
B. Negative
C. Zero
D. Stable

Explanation

To solve the question regarding the electromotive force (EMF) of a cell where oxidation and reduction take place, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Electromotive Force (EMF)**:
- Electromotive force (EMF) is defined as the electric potential produced by an electrochemical cell. It is the measure of the energy provided by the cell per coulomb of charge.

2. **Identify the Reactions in the Cell**:
- In an electrochemical cell, oxidation and reduction reactions occur simultaneously. Oxidation involves the loss of electrons, while reduction involves the gain of electrons. Together, these reactions are known as redox reactions.

3. **Determine the Condition for EMF**:
- For a cell to function and produce a positive EMF, it must have a spontaneous reaction. A spontaneous reaction occurs when the cell potential (E_cell) is greater than zero.

4. **Conclusion**:
- Since oxidation and reduction are taking place in the cell, it indicates that a redox reaction is occurring. For this reaction to be spontaneous, the electromotive force (E_cell) must be positive. Therefore, the correct answer is that the electromotive force will be positive.

### Final Answer:
The electromotive force (EMF) will be **positive** when oxidation and reduction take place in a cell.

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