This article explains the key differences between galvanic cell and electrolytic cell on the basis of energy conversion, Redox Reaction, Polarity, Electron Flow, Material, Ions Discharge, Electrons Supply, Chemical Reaction, and Uses.
A galvanic cell is the one in which an oxidation-reduction chemical reaction occurs spontaneously to generate electrical energy. Chemical energy is converted into electrical energy.
An electrolytic cell is the one in which electrolysis process takes place, a chemical compound is disintegrated by passing electricity through it. The chemical reaction taking place is not self-generated (spontaneous), it is forced by employing a voltage.
The two cells also differ considerably with regard to the electric charges on the electrodes. For instance, in galvanic cell anode is negative while in an electrolytic cell, the anode has a positive charge. Likewise, the cathode is positive in an electrochemical cell, the cathode has negative charge whilst it is negative in the electrolytic cell.
In electrochemistry, oxidation and reduction chemical reaction play a crucial part. In such chemical reactions, electrons are being transferred from one reactant to another. The element that takes electrons is called a reducing agent, whereas the element that leaves the electron is recognized as the oxidizing agent. The reducing agent is accountable to reduce the other reactant whilst experiencing oxidation itself. And for oxidizing agent, it is vice versa. Such chemical reactions can be separated into two half-reactions, to demonstrate separate oxidations and reductions.
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Difference between Galvanic Cell and Electrolytic Cell
Characteristics | Electrolytic cells | Galvanic cells |
---|---|---|
Energy conversion | Electric energy is converted into chemical energy | Chemical energy is converted into electric energy |
Redox reaction | Electric energy brings about a redox reaction | Electric energy is generated by a redox reaction |
Oxidation/Reduction Process | Redox reaction takes place in the same container | Oxidation and reduction reactions are carried out separately |
Salt bridge | No salt bridge is required | Generally salt bridge is required |
Ions discharge | Ions discharged at both the electrodes | Ions discharged at the cathode while anode is consumed |
Polarity | Anode is positive while cathode is negative | Anode is negative while cathode is positive |
Electrons flow | Electrons move from anode to cathode through external circuit | Electrons move from cathode to anode through external circuit |
Electricity Measurement | The amount of electricity passed is measured by a coulometer | The emf of the cell is measured by a potentiometer |
Material | One electrolyte and two electrodes of the same material are generally used in these cells | Two different electrolytes and two different electrodes are used in these cells. |
Chemical reaction | Chemical reaction is forced by applying a certain voltage (NOT spontaneous) | Chemical reaction is spontaneous |
Electrons Supply | Electrons are supplied to the cell from an external source | Electron are drawn from the cell |
Uses | Electroplating and purifying Copper | Batteries |