Question

The number of incorrect statements from the following is _____
A. The electrical work that a reaction can perform at constant pressure and temperature is equal to the reaction Gibbs energy.
B. E°_cell is dependent on the pressure.
C. dE^θ cell/dT = Δ_rS^θ/nF
D. A cell is operating reversibly if the cell potential is exactly balanced by an opposing source of potential difference.

Hint:

Carefully evaluate each statement in electrochemistry questions to determine its validity based on thermodynamic and standard definitions

Answer 1

Correct Answer: 1

Analysis of Statements on Electrochemical Reactions:

1. Statement 1: The first statement is correct because, under constant pressure and temperature, the electrical work of a reaction equals the Gibbs free energy (\( \Delta G \)).
2. Statement 2: The second statement is incorrect. The standard cell potential (\( E^\circ_{\text{cell}} \)) is defined under standard conditions (1 atm pressure, 298 K), so it is not dependent on pressure.
3. Statement 3: The third statement is correct, as the relationship between \( E^\circ_{\text{cell}} \) and temperature involves entropy (\( \Delta S^\circ \)): \[ \frac{dE^\circ_{\text{cell}}}{dT} = \frac{\Delta S^\circ}{nF}. \]
4. Statement 4: The fourth statement is correct, as a cell operates reversibly when its potential is perfectly balanced by an opposing source of potential difference.

Conclusion:

There is 1 incorrect statement (Statement 2).