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In many electrode reactions electrodes do not behave ideally, as some times the gaseos products obtained get adsorbed on the electrode surface which hindes the electrode reactions. This slow down of electrode reactions can be over come by some extra potential. This is known as “over potential”.

Overpotential is an electrochemical term which directs to the voltage difference (potential) between a Half- Cell reaction’s thermodynamically determined reduction potential and the potential at which the redox event is experimentally observed.

Due to overpotential:

  • An electrolytic cell’s anode is more positive using more energy than thermodynamics require.
  • An electrolytic cell’s cathode is more negative using more energy than thermodynamics require.
  • A galvanic cell’s anode is less negative supplying less energy than thermodynamically possible.
  • A galvanic cell’s cathode is less positive supplying less energy than thermodynamically possible

Over Potential is a measure of the shift of the tendency of an for the reaction/ interaction b/w electrode and ions for electrode reaction.

Over Potential

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