Identify the incorrect statement among the following ?

Options

A. A salt bridge is used to eliminate liquid junction potential in a galvanic cell
B. The Gibbs free energy change , `DeltaG` is related with electromotive force (E), as `DeltaG=-nFE`
C. Nernst equation for single electrode potential is given by `E=E^@-(RT)/(nF)In[M^(n+)]`
D. The maximum theoretical efficiency of a hydrogen oxygen fuel cell is 33%

Answer

To solve the question of identifying the incorrect statement among the provided options, we will analyze each statement one by one.

### Step 1: Analyze Option 1
**Statement:** A salt bridge is used to eliminate liquid junction potential in a galvanic cell.

**Evaluation:** This statement is correct. A salt bridge is indeed used in galvanic cells to maintain electrical neutrality by allowing the flow of ions, which helps eliminate the liquid junction potential.

### Step 2: Analyze Option 2
**Statement:** The Gibbs free energy change (ΔG) is related to emf (electromotive force) as ΔG = -nFE.

**Evaluation:** This statement is also correct. The relationship between Gibbs free energy change and electromotive force is given by the equation ΔG = -nFE, where n is the number of moles of electrons transferred, F is Faraday's constant, and E is the emf of the cell.

### Step 3: Analyze Option 3
**Statement:** The Nernst equation for a single electrode potential is given by E = E0 - (RT/nF) ln(n⁺).

**Evaluation:** This statement is incorrect. The correct form of the Nernst equation for a single electrode potential is E = E0 + (RT/nF) ln([A]/[Mn⁺]), where [A] is the concentration of the species and [Mn⁺] is the concentration of the ions. The sign and the logarithmic base are important here.

### Step 4: Analyze Option 4
**Statement:** The maximum theoretical efficiency for hydrogen-oxygen fuel cells is 33%.

**Evaluation:** This statement is correct. The maximum theoretical efficiency of hydrogen-oxygen fuel cells is indeed around 33%, which is a well-established fact in electrochemistry.

### Conclusion
After evaluating all the statements, we find that the incorrect statement is **Option 3**.

### Final Answer
The incorrect statement is **Option C**.

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