What is the Difference Between Electrolytic and Galvanic Cells?

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The main difference between electrolytic and galvanic cells lies in the spontaneity of the redox reactions and the energy source required. Here are the key differences:

  • Galvanic Cells:
  • Also known as Voltaic cells.
  • Derive energy from spontaneous redox reactions.
  • Converts chemical energy into electrical energy.
  • Continuous flow of electrons through the conductor.
  • Applications include batteries.
  • Electrolytic Cells:
  • Involve non-spontaneous reactions.
  • Require an external electron source, such as a DC battery or an AC power source.
  • Convert electrical energy into chemical energy.
  • Electrodes can be placed in a single compartment containing the molten or solution electrolyte.
  • Applications include purifying copper and electroplating.

Both galvanic and electrolytic cells consist of two electrodes (an anode and a cathode) and an electrolyte in which the two electrodes are immersed. However, the energy conversion in galvanic cells is spontaneous, whereas electrolytic cells require an external energy source to drive the non-spontaneous reactions.

Comparative Table: Electrolytic vs Galvanic Cells

Here is a table comparing the differences between electrolytic and galvanic cells:

Feature Galvanic Cells Electrolytic Cells
Spontaneity Spontaneous redox reactions convert chemical energy to electric energy. Non-spontaneous redox reactions convert electric energy to chemical energy using an external source.
Electric Energy Generates electric energy through redox reactions. Requires an external source of electric energy to initiate redox reactions.
Electrode Config The cathode is the positive electrode, and the anode is the negative electrode. The anode is the positive electrode, and the cathode is the negative electrode.
Configuration Half cells are set up in different containers and connected through salt bridges. Electrodes are in the same container in a molten or solution electrolyte.
Applications Commonly used in batteries. Applied in purifying metals and electroplating.

In summary, galvanic cells convert chemical energy into electrical energy through spontaneous redox reactions, while electrolytic cells use an external source of electric energy to drive non-spontaneous redox reactions. The placements of the cathode and anode are also reversed between the two types of cells.