Chlorinated Swimming Pools
- Page ID
- 50880
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If you have been to a public pool, then you are likely familiar with chlorinated water, which gives of a distinct, slightly irritating smell. When swimming, such water can also irritate the eyes if one is not wearing goggles. While both these effects are irritating, they are clearly necessary to keep a pool sanitary. As you may guess, chlorinated pools, and their ability to remain sanitary, are related to halogen chemistry.
Large-scale projects, such as city water supplies, use elemental chlorine, liquefied and stored under pressure, to keep water sanitary. Because it is a strong oxidizing agent, Cl2 can destroy harmful microorganisms, making water safe to drink.
Pools themselves are chlorinated by a different method. Hypochlorous acid, HOCl, is a weak acid. In basic solution the halogen is completely consumed, producing the hypohalite anion:
\(\ce{Cl2 + 2OH- -> Cl- + H2O + OCl-}\)
Since hypochlorite, OCl–, could also be supplied from an ionic compound such as NaOCl, the latter is often used to chlorinate swimming pools. OCl–, like Cl2 is a strong oxidizing agent, and thus destroys microorganisms as well.
From ChemPRIME: 12.7: Group VIIA: Halogens
Contributors and Attributions
Ed Vitz (Kutztown University), John W. Moore (UW-Madison), Justin Shorb (Hope College), Xavier Prat-Resina (University of Minnesota Rochester), Tim Wendorff, and Adam Hahn.