Cathode: Definition, Examples, and Anode vs Cathode

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What is Cathode?

o The terms Cathode and Anode were confirmed in 1834 by a scientist named William Whewell. He derived the words from the Greek word, kathodos which means ‘way down’ In simple words, an electrode is defined as a substance that helps in the conduction of electricity where the electric current either arrives or leaves the non-metallic medium like an electrolytic cell.


o An electrode is referred to as the vital component of an electrochemical cell that makes contact with an electrolyte.

o Electrode usually acts as a metallic contact from which the current enters and leaves the electrolyte.

o More precisely, it can be said that the electrode provides a surface where a redox reaction generally takes place between the metal and the solution.

Types of Electrode

Electrodes comprise of;

i. Cathode

ii. Anode

Cathode Characteristic

o Cathode and anode are both defined by the flow of current. Consequently, a cathode is an electrode from which the current leaves a polarized electrical device.

o Similarly, an anode is an electrode from which a current generally enters into a polarized electrical device.

o Further, a cathode is also said to be either a hot cathode or a cold cathode.

o A cathode is heated in the presence of a filament to produce electrons by thermionic emission is commonly known as a hot cathode however cold cathodes are not heated by any filament.

o A cathode is generally labeled as cold if it emits more electrons than the ones produced by thermionic emission alone.

o In the most simple terms, an anode in electrochemistry is referred to the point where an oxidation reaction occurs.

o Commonly, at an anode, negative ions or anions because of their electrical potential tend to react or give off electrons.

Flow of Current

o In simple words, the current is referred to any movement of electrical charge.

o Current generally flows in the same direction as it flows in positive charge carriers.

o The cathode is the negatively charged electrode.

o Few points of the cathode are mentioned below;

o The cathode always attracts cations or positive charges.

o The cathode is the source of electrons or also called an electron accepter and can cause reduction to occur. It may take a positive charge.

o Because the cathode producess electrons, which naturally are the electrical species, it can also be said that cathodes produce charge or that the current flows from the cathode to the anode.

Anode vs Cathode

Some important differences between cathode and anode are mentioned below;

The anode is defined as the electrode where electricity moves into.The cathode is defined as the electrode where electricity is given out or flows out of.
The anode is generally the positive side.A cathode is always the negative side.
It acts as an electron donor.It acts as an electron acceptor.
In an electrolytic cell, an oxidation reaction usually takes place at the anode.In an electrolytic cell, a reduction reaction usually takes place at the cathode.
In galvanic cells, an anode can also become a cathode.In galvanic cells, a cathode can also become an anode

Cathode Citations


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