Arrange the following in the order of their decreasing electrode oxidizing potential Mg, K, Ba, Ca
Ba, Ca, K, Mg
K, Ba, Ca, Mg
Ca, Mg, K, Ba
Mg, Ca, Ba, K
As we have learnt,
It is the potential difference between the two terminals of the cell when no current is drawn from it. It is measured with the help of potentiometer or vacuum tube voltmeter.
Calculation of the EMF of the Cell
Mathematically, it may be expressed as
Difference between EMF and Cell Potential
EMF | Cell Potential |
It is measured by potentiometer. |
It is measured by voltmeter. |
It is potential difference between two electrodes when no current is flowing in the circuit. |
It is potential difference between two electrodes when current is flowing through the circuit. |
It is maximum voltage obtained from cell. |
It is less than maximum voltage. |
It corresponds to maximum useful work obtained from galvanic cell. |
It does not correspond. |
- wherein
The correct order can be obtained from electrochemical series.
Therefore, Option(2) is correct