Difference Between emf and Potential Difference
Emf | Potential difference |
| It is the potential difference between two electrodes when no current is flowing in the circuit. | It is the difference of the electrode potentials of the two electrodes when the cell is under operation. |
| It is the maximum voltage that the cell can deliver. | It is always less then the maximum value of voltage which the cell can deliver. |
| It is responsible for the steady flow of current in the cell. | It is not responsible for the steady flow of current in the cell. |
Cell EMF and the spontaneity of the reaction : We know, 
| Nature of reaction |  |  |
| Spontaneous | – | + |
| Equilibrium | 0 | 0 |
| Non – spontaneous | + | – |
