Galvanic Cell Definition (Voltaic Cell)

What Is a Galvanic Cell?

Battery driven by electrolyte concentrations porous vase version

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A galvanic cell is a cell where chemical reactions between dissimilar conductors connected through an electrolyte and a salt bridge produce electric energy. A galvanic cell can also be powered by spontaneous oxidation-reduction reactions. Essentially, a galvanic cell channels the electrical energy produced by the electron transfer in a redox reaction. The electrical energy or current may be sent to a circuit, such as in a television or light bulb.

The electrode of the oxidation half-cell is the anode (-), while the electrode of the reduction half-cell is the cathode (+). The mnemonic "The Red Cat Ate an Ox" may be used to help remember reduction occurs at the cathode and oxidation occurs at the anode.

A galvanic cell is also called a Daniel cell or a voltaic cell.

How to Set Up a Galvanic Cell

There are two main setups for a galvanic cell. In both cases, the oxidation and reduction half-reactions are separated and connected via a wire, which forces electrons to flow through the wire. In one setup, the half-reactions are connected using a porous disk. In the other setup, the half-reactions are connected via a salt bridge.

The purpose of the porous disk or salt bridge is to allow ions to flow between the half-reactions without much mixing of the solutions. This maintains charge neutrality of the solutions. The transfer of electrons from the oxidation half-cell to the reduction half-cell leads to a buildup of negative charge in the reduction half-cell and of positive charge in the oxidation half-cell. If there were no way for ions to flow between the solution, this charge build-up would oppose and half the electron flow between the anode and cathode.

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Helmenstine, Anne Marie, Ph.D. "Galvanic Cell Definition (Voltaic Cell)." ThoughtCo, Aug. 28, 2020, Helmenstine, Anne Marie, Ph.D. (2020, August 28). Galvanic Cell Definition (Voltaic Cell). Retrieved from Helmenstine, Anne Marie, Ph.D. "Galvanic Cell Definition (Voltaic Cell)." ThoughtCo. (accessed March 4, 2021).