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Read About Electrolysis: Meaning, Process, Application and Water electrolysis.

Updated on 07 December 2021
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NEET Preparation
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Updated on 07 December 2021

Q: What is the definition of electrolysis ?


The process of decomposition of ionic compounds into their constituent elements by passage of direct electric current through the compound available in a fluid form is known as electrolysis.


Electrolysis in detail


Michael Faraday coined the word electrolysis in the nineteenth century. It was a method for acquiring pure elements in the study of chemical processes. Electrolysis is now frequently utilized in separating or getting pure elements from naturally occurring sources such as ores, making it a commercially relevant process.


The process of decomposition of ionic compounds into their constituent elements by passage of direct electric current through the compound available in a fluid form is known as electrolysis. At the cathode, cations are reduced, whereas anions are oxidized at anode. An electrolyte, electrodes, and some type of external power source are necessary for conducting electrolysis. A partition, such as an ion-exchange membrane or a salt bridge, may also be utilized to prevent products from diffusing too close to the opposing electrode.


By flowing electric current through acidified or salt-containing water, can lead to its decomposition into its constituent elements- hydrogen. Sodium and chlorine atoms can also be separated from molten sodium chloride with the help of electrolysis process.


Electrolysis is usually performed in a 'electrolytic cell,' which consists of a vessel with two electrodes (cathode and anode) connected to a direct current source and an electrolyte, which is an ionic compound in the process of decomposition, in either molten form or dissolved in a suitable solvent. Electrodes consisting of metal, graphite, and semiconductor materials are commonly utilized. The selection of an appropriate electrode, on the other hand, is dependent on the chemical reactivity of the electrode with the electrolyte as well as the manufacturing cost.


The process of electrolysis


The addition or removal of electrons from the external circuit causes an exchange of ions and atoms in the electrolysis process. Cations migrate to the cathode as current passes, take electrons from the cathode (provided by the supply source-battery), and discharge into the neutral atom. The neutral atom is deposited on the cathode if it is solid, and it moves upwards if it is gas. The cation is reduced at the cathode in this reduction process.


At the same time, anions donate their additional electrons to the anode, where they are oxidized to neutral atoms. Anions release electrons that move across the electrical circuit to the cathode, completing the circuit. A simultaneous oxidation reaction at the anode and a reduction reaction at the cathode are involved in electrolysis.


When an electric current is delivered through molten sodium chloride, for example, the sodium ion is drawn to the cathode, where it takes an electrode and transforms into a sodium atom.

When the chloride ion reaches the anode, it gives up its electron and transforms into a chlorine atom, which then forms a chlorine molecule.


Na+ (in the electrolyte) + e– (from the cathode) = Na....


At the anode, Cl–(from electrolyte) e– + Cl Cl2....


While the electrolysis process can be used directly to extract elemental forms from compounds, it can also be utilized indirectly in the metallurgy of alkali and alkaline earth metals, metal purification, metal deposition, and compound production.



Applications of electrolysis


As previously stated, electrolysis is the process of changing the ions of a liquid chemical into their reduced or oxidized state by passing an electric current through it. As a result, electrolysis has a wide range of uses in both experimental and industrial products.

The following are a few of the most important uses of electrolysis:


1) Alkali and alkaline earth metal metallurgy.

2) Metals purification.

3) Production of clean gases

5)Production of chemicals such as sodium hydroxide, sodium carbonate, and potassium chlorate, among others.

6) Providing resistance against corrosion via electroplating



Electrolysis of water


Electrolysis of water is a chemical reaction in which an electric current is used to carry out the decomposition of hydrogen and oxygen gases. Water electrolysis is mostly used to produce clean hydrogen and oxygen gases. In this process an electric current over water, causing the water to decompose into hydrogen and oxygen.


The electrolysis of water equation is as follows:


Half-reactions in pure water electrolysis at pH=7 and at 25°Care


2H2O(l) + 2e– H2(g) + 2OH– E° = -0.42 V at the cathode


2H2O O2(g) + 4H+ + 4e– E° = +0.82 V at anode


The net response of water electrolysis is as follows:


E° = -1.24 V 2H2O + Electrical energy O2 + 2H2 E° = -1.24 V


As a result, the number of hydrogen molecules created is double that of oxygen molecules. Hydrogen is collected at the negative anode after electrolysis of water, whereas oxygen is collected at the positive anode. Hydrogen has double the volume of oxygen.

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