Any redox reaction would occur spontaneously, if:-

Options

A. the free energy change `(DeltaG)` is negative
B. the `(DeltaG)` is positive
C. the cell e.m.f `(E^(@))` is negative
D. the cell e.m.f. is positive

Answer

To determine the conditions under which any redox reaction would occur spontaneously, we can analyze the relationship between the standard electromotive force (EMF) of the cell and the Gibbs free energy change (ΔG°) of the reaction.

### Step-by-Step Solution:

1. **Understanding Spontaneity of Reactions**:
- A redox reaction is said to be spontaneous if it can occur without any external influence. This is often assessed by looking at the cell potential (E°) and the Gibbs free energy change (ΔG°).

2. **Relationship Between ΔG° and E°**:
- The relationship between the Gibbs free energy change and the standard EMF of the cell is given by the equation:
\[ \Delta G° = -nFE° \]
where:
- \( \Delta G° \) = change in Gibbs free energy
- \( n \) = number of moles of electrons transferred
- \( F \) = Faraday's constant (approximately 96485 C/mol)
- \( E° \) = standard EMF of the cell

3. **Condition for Spontaneity**:
- From the equation, we can deduce:
- If \( E° > 0 \) (positive EMF), then \( \Delta G° < 0 \) (negative Gibbs free energy), indicating that the reaction is spontaneous.
- Conversely, if \( E° < 0 \) (negative EMF), then \( \Delta G° > 0 \) (positive Gibbs free energy), indicating that the reaction is non-spontaneous.
- If \( E° = 0 \), the system is at equilibrium.

4. **Conclusion**:
- Therefore, any redox reaction will occur spontaneously if:
- The standard EMF of the cell (E°) is positive.
- Alternatively, if the Gibbs free energy change (ΔG°) is negative.

### Final Answer:
Any redox reaction would occur spontaneously if:
- The standard EMF (E°) of the cell is positive.
- The Gibbs free energy change (ΔG°) is negative.