Emf of a Cell

EMF of a Cell

The electromotive force of a cell, or EMF for short, is the highest potential difference between two electrodes of a cell. The net voltage between the oxidation and reduction half-reactions is also known as the net voltage. EMF is mostly used to determine whether or not an electrochemical cell is galvanic.

We’ll go over key formulas and how to calculate the EMF of an electrochemical cell in this session.

What is the definition of EMF of a Cell

An electrochemical cell is a device that generates electricity through a chemical reaction. It is an apparatus that converts chemical energy into electrical energy. An electrochemical cell must go through a chemical reaction that involves the exchange of electrons in order to function. When two different compounds react in the same way, this is referred to be a redox reaction.

Temperature variations, concentration fluctuations, and other factors can cause the cell voltage to differ from this ideal value. The EMF value can be calculated using the Nernst equation, which was created by Walther Nernst if the cell’s standard cell potential is known.

Electrochemical Cells Come in a Variety of Shapes and Sizes

Cellular Galvanic

Luigi Galvani, an Italian scientist, was given the moniker Galvanic Cell. A galvanic cell is a type of electrochemical cell that serves as the foundation for many others, such as the Daniell cell. It is made up of two electrodes, which are separate metallic conductors immersed in their own ionic solutions. This is a half-cell configuration. A half cell cannot produce a potential difference on its own. However, when they are used together, they can make a significant difference. The two cells are chemically connected using a salt bridge. It transfers electrons from the electron-rich half cell to the electron-deficient half cell as needed.

Daniell Cell

A galvanic cell has been converted into a Daniell cell. Zinc and copper electrodes are submerged in zinc and copper sulphate solutions, respectively. A salt bridge connects two half cells. Copper is utilised as the cathode while zinc is used as the anode.

When compared to copper metal, zinc metal ranks first in the electrochemical series due to its larger oxidation potential. As a result, zinc is oxidised, resulting in the generation of two electrons and a zinc ion. In comparison to the other electrode, this electrode develops a negative potential as a result of electron release. The anode is how we refer to it.

Copper, on the other hand, is decreased due to its greater reduction potential. In the copper half-cell solution, the copper ion absorbs two electrons from the electrode and converts them into copper metal, which is subsequently deposited in the electrode. We call this electrode a cathode because it consumes electrons and is considered a positive electrode.

The following is an illustration of the anode reaction:

2e^– Zn(s) Zn²⁺ (aq) Zn(s) Zn(s) Zn(s) Zn(s) Zn(s) Zn(s)

The following is an illustration of the cathode reaction:

Cu²⁺ +2e^– Cu²⁺ (aq) Cu²⁺ (aq) Cu²⁺ (aq) Cu²⁺ (aq) (s)

The following is the overall or integrated cell reaction:

Cu²⁺(aq) + Zn(s) + Cu²⁺(aq) + Cu²⁺ (aq) + Cu²⁺ (aq) + Cu²⁺ (aq) + Cu²⁺ (aq) + Cu²⁺ (s)

Potential Electrode

A potential difference across the contact is created when a metal electrode is immersed in a solution containing its own ions. The electrode potential is defined as the difference in potential between two electrodes.

The zinc metal oxidises and disappears in water after releasing two electrons. A potential difference is created when electrons in an electrode hit ions in a solution. Copper, too, has a bright future ahead of it. The combined cell potential of these two cells is very high.

The difference in the potentials of the two half cells makes up this overall potential. A good example of a standard half cell is the standard hydrogen electrode (SHE). SHE’s potential is set to zero volts by design. The potential difference is determined when a conventional hydrogen electrode is coupled to an unknown half cell. The potential difference of the unknown half cell will be detected because SHE has zero volts.

The method to determine zinc’s standard electrode potential is depicted in the diagram below.

Serie Electrochimique

Similarly, the electrochemical series is created by calculating the standard potential values of various metals and then arranging them in increasing order of potential.

For the determination of cell potential, electrochemical series is necessary. It can also aid in the selection of electrode metals for use in cell building.

The electrochemical series table depicts the order in which a few elements’ reduction potentials increase. The least reduction potential is lithium, while the largest is fluorine. The reduction potential of hydrogen is zero. This is because the standard electrode potential of all other elements is calculated by comparing them to hydrogen.

Also read: JEE Advanced Sample Papers

(FAQs) Frequently Ask Question for EMF of a Cell

What is a cell's electromotive force (emf)?

The EMF of a Cell The electromotive force of a cell, or EMF of a cell, is the highest potential difference between two electrodes of a cell. It's also known as the net voltage between oxidation and reduction half-reactions. The EMF of an electrochemical cell is mostly used to determine whether or not it is galvanic.

What is an electromagnetic field (EMF) and why is it important?

The EMF of a cell is mostly used to determine whether or not it is galvanic. The potential difference is the calculation of energy between any two points on a circuit. The EMF is the greatest voltage the battery will produce, although the size of the potential difference is always smaller than the highest theoretical value of emf.