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Electrochemical Cell

Electrolytic Cells

There are many chemical reactions that, unlike the sodium-chlorine and copper-silver reactions above, simply will not occur spontaneously. One example is the breakup of water into hydrogen and oxygen:

This will not happen all by itself (that is, without the added energy) because water is an extremely stable compound. We can force this reaction to go, however, by pumping energy into the water in the form of an electric current. When we do this—passing an electric current through a chemical system in order to drive chemical reactions happen—creates an electrolytic cell.

Electrolytic cells are used for a variety of purposes other than the electrolysis of water. They are used for obtaining metals such as sodium, magnesium, and aluminum from their compounds; for refining copper; for producing important industrial chemicals such as sodium hydroxide, chlorine, and hydrogen, and for electro-plating metals such as silver, gold, nickel, and chromium onto jewelry, tableware, and industrial machine parts.

Sea also Bond, chemical.

Resources

Books

Chang, Raymond. Chemistry. New York: McGraw-Hill, 1991.

Oxtoby, David W., et al. The Principles of Modern Chemistry. 5th ed. Pacific Grove, CA: Brooks/Cole, 2002.

Umland, Jean B. General Chemistry. St. Paul: West, 1993.


Robert L. Wolke

KEY TERMS

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Anode

—A positively charged electrode.

Cathode

—A negatively charged electrode.

Electrode

—A conductor, usually a piece of metal, used to lead electricity (electrons) into or out of a region.

Electrolysis

—The process by which an electrical current is used to break a compound apart into its components.

Electrolyte

—The chemical solution in which an electric current is carried by the movement and discharge of ions.

Oxidation

—The process in which an atom's oxidation state is increased, by its losing one or more electrons.

Oxidation state or oxidation number

—A positive or negative whole number that expresses how many units of combining power an atom is exhibiting toward other atoms. For example, sodium in NaCl has an oxidation number of +1, while sulfur in Na2S has an oxidation number of 2.

Oxidation-reduction reaction

—A chemical reaction in which one or more atoms are oxidized, while one or more other atoms are reduced.

Reduction

—The process by which an atom's oxidation state is decreased, by its gaining one or more electrons.

Additional topics

Science EncyclopediaScience & Philosophy: Categorical judgement to ChimaeraElectrochemical Cell - Chemistry And Electricity, Voltaic Cells, Electrolytic Cells