Chlorine demand definition

If handled responsibly, PFCs can be excellent choices to replace ozone-depleting compounds in many demanding, high-performance applications. Perfluorinated liquids are colorless, odorless, essentially nontoxic, and nonflammable. In addition, since they are not precursors to photochemical smog, PFCs are exempt from the U.S. EPAs volatile organic compounds (VOC) definition. Most importantly, these materials do not contain the carbon-bound chlorine or bromine, which can cause ozone depletion. 

For over a century this definition sufficed. It was, nevertheless, unsatisfactory, being neither more nor less than a confession of ignorance and impotence. Thus it demanded that caustic potash should be regarded as an element until Davy succeeded in decomposing it by electrolysis in 1807. Similarly lime was regarded as an element and when Charles Tennant chlorinated slaked lime in 1799, the product was perforce called chloride of lime, a name that clings to it even to-day. 

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