Electrolytic Cell: Definition, Diagram, Working, Uses

Electrolytic Cell: An electrolytic cell is an electrochemical device that uses electrical energy to help a non-spontaneous redox reaction take place. Electrolytic cells are electrochemical cells that may be used to electrolyze a variety of substances. Water, for example, may be electrolyzed (using an electrolytic cell) to produce gaseous oxygen and gaseous hydrogen. This is done by using the flow of electrons (into the reaction environment) to overcome the non-spontaneous redox reaction’s activation energy barrier. On this page let us learn everything about electrolytic cell in detail. Read further to find more.

What is Electrolysis?

Electrolysis may be defined as a process of decomposition of an electrolyte by the passage of electricity through its aqueous solution or molten state. The apparatus to bring about this change is the Electrolytic cell.

Mechanism of Electrolysis

Whenever an electrolyte is dissolved in water or taken in a molten state- on passing electric current, the electrolyte dissociates to produce positively and negatively charged ions. The positively charged ions move towards the cathode, and the negatively charged ions move towards the anode.
On reaching their respective electrodes, the ions lose their charge and become neutral particles. The cations accept electrons from the cathode, and anions donate electrons to the anode. Thus, oxidation occurs at the anode and reduction at the cathode.

What is Electrolytic Cell?

An electrolytic cell is an electrochemical device that uses electrical energy to drive a non-spontaneous redox reaction. They are electrochemical cells that are usually used to conduct the electrolysis of certain compounds.
The electrolysis process is carried out by using the flow of electrons into the reaction to overcome the threshold energy barrier of the non-spontaneous redox reaction.
For example, water undergoes electrolysis to produce hydrogen gas and oxygen gas. This process is carried out with the help of additional energy- electrical energy. An electrolytic cell has three components,
(i) Electrolyte
(ii) Cathode
(iii) Anode
The electrolyte taken is usually a solution of water or any other solvents in which ions are dissolved. It acts as a medium for the exchange of electrons between the two electrodes takes place.

What is a non-spontaneous Redox Reaction?

When an external voltage is applied to carry out a redox reaction, it is termed a non-spontaneous redox reaction, whereas a spontaneous redox reaction itself creates a voltage.

Working of an Electrolytic Cell

An electrolytic cell is a device that converts electrical energy into chemical energy. Let us understand the working with the help of the process of electrolysis of sodium chloride.

Two electrodes are dipped in the molten sodium chloride, and the electrodes are connected to a source of direct electric current. When an electric current is passed through the circuit, one of the electrodes becomes negatively charged-cathode, and the other becomes positively charged-anode. The positively charged sodium ions get attracted towards the cathode, which results in the formation of metallic sodium at the cathode.

Similarly, the negatively charged chloride ions get attracted towards the anode, which results in the formation of chlorine gas at the anode. Thus, oxidation reaction occurred at the anode and reduction reaction at the cathode.

The following reactions take place-
1. At Cathode: \({\rm{N}}{{\rm{a}}^ + } + {{\rm{e}}^ – } \to {\rm{Na}}\)
2. At Anode: \(2\,{\rm{C}}{{\rm{l}}^{\rm{ – }}} \to {\rm{C}}{{\rm{l}}_{\rm{2}}} + 2\,{{\rm{e}}^ – }\)
3. Cell reaction: \(2\,{\rm{NaCl}} \to 2\,{\rm{N}}{{\rm{a}}^{\rm{ + }}} + {\rm{C}}{{\rm{l}}^{\rm{ – }}}\)

Applications of Electrolytic Cell

It is used to extract metals like zinc from its ore and aluminium from bauxite and cryolite, and the process is called Electrometallurgy.
The electrolytic cell is primarily utilized for the production of hydrogen gas and oxygen gas.
Many chemicals like caustic soda, chlorine gas, etc., are produced on a large scale by the electrolytic cell.
Commercially, electrolytic cells are used for the Electrorefining and electrowinning of several non-ferrous metals.
One of the most important application is electroplating. It is the process of a thin coating of a specific metal over the surface of another metal.

Difference between Galvanic Cell and Electrolytic Cell

Based on electrochemical changes occurring in electrochemical cells, they can be divided into the galvanic cell and electrolytic cell based on the electrochemical changes occurring in electrochemical cells. The difference between them is as follows:

Galvanic Cell	Electrolytic Cell
It is the device to convert chemical energy into electrical energy i.e., electrical energy is produced because of redox reaction.	It is the device to convert electrical energy into chemical energy i.e., chemical energy is produced because of redox reaction.
It is based on a redox reaction which is spontaneous.	The redox reaction is non-spontaneous and takes place only when the electrical energy is supplied.
Two different electrodes are usually set up in two separate beakers.	Both the electrodes, either of the same material or different material, are suspended in the electrolytic solution in the same beaker.
Two different electrolytes are taken in two separate beakers.	Only one electrolyte is taken.
The electrode on which oxidation takes place is called the anode (negative pole), and the electrode on which reduction takes place is the cathode (positive pole).	The electrode which is connected to the negative terminal of the battery is called the cathode, and reduction occurs here. Oxidation occurs in the anode, i.e., the electrode connected to the positive terminal
To set this cell, a salt bridge/porous pot is used.	No salt bridge is used in the electrolytic cell.
\(\left( {\Delta {\rm{G}}} \right)\) that is energy change during the reaction is negative, due to production of electrical energy.	\(\left( {\Delta {\rm{G}}} \right)\) that is energy change during the reaction is positive due to the production of chemical energy.

Summary

Through this article, you explored the meaning, working and applications of the electrolytic cell. Also, you learned the difference between the galvanic cell and electrolytic cell. Some of the useful applications of electrolytic cell are:

The creation of oxygen and hydrogen gas from water is the major use of electrolytic cells.
They may also be used to recover aluminium from bauxite.
Electroplating, which is the process of creating a thin protective coating of a certain metal on the surface of another metal, is another famous use of electrolytic cells.
Electrolytic cells are used in the electrorefining of numerous non-ferrous metals.
Electrochemical cells like this are also employed in electrowinning.

FAQs on Electrolytic Cell

Q.1. Where is electrolytic cell used for?
Ans: The electrolytic cell is primarily utilized for the production of hydrogen gas and oxygen gas. Commercially, electrolytic cells are used for the Electrorefining and electrowinning of several non-ferrous metals.

Q.2. What is an electrolytic cell, and how does it work?
Ans:An electrolytic cell is a device that converts electrical energy into chemical energy.
Whenever an electrolyte is dissolved in water or taken in a molten state- on passing electric current, the electrolyte dissociates to produce positively and negatively charged ions. The positively charged ions move towards the cathode, and the negatively charged ions move towards the anode. On reaching their respective electrodes, the ions lose their charge and become neutral particles. The cations accept electrons from the cathode, and anions donate electrons to the anode. Thus, oxidation occurs at the anode and reduction at the cathode.

Q.3. What is the principle of the electrolytic cell?
Ans: An electrolytic cell works on the mechanism of non-spontaneous redox reaction. The cations accept electrons from the cathode, and anions donate electrons to the anode. Thus, oxidation occurs at the anode and reduction at the cathode.

Q.4. What are the components of the Electrolytic cell?
Ans: The three components of the electrolytic cell are- the cathode, the anode and the electrolyte.

Q.5. What type of charges do the electrodes of n electrolytic cell carry?
Ans: In an electrolytic cell, the cathode is negatively charged, and the anode is positively charged. The positive ions get attracted toward the cathode, and the negative ions get attracted towards the anode.

Q.6. When can an electrochemical cell behave like an electrolytic cell?
Ans: If a potential difference greater than the potential of the electrochemical cell is applied, the electrochemical cell behaves like the electrolytic cell.

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