NANFA-- new improved pH definition

Bruce Stallsmith (
Tue, 04 Dec 2001 19:42:44 -0500

This pH question has been bugging me for the last hour or so; I consulted a
bunch of textbooks including Biochemistry and Animal Phys. But none of them
addressed the following definition, where does the "p" in pH come from. My
original statement that p is for the French "pouvoir" is kinda right but not
the whole story; here's something I found that is consistent with my nagging
thought that the Germans, not the French, were the great chemists of 100
years ago. (Making the Dane, Sorensen, an honorary German I suppose...!):

The Simple Definition

pH is a logarithmic measure of hydrogen ion concentration, originally
defined by Danish biochemist Søren Peter Lauritz Sørensen in 1909 [1].

pH = -log[H+]

where log is a base-10 logarithm and [H+] is the concentration of hydrogen
ions in moles per liter of solution. According to the Compact Oxford English
Dictionary, the "p" stands for the German word for "power", potenz, so pH is
an abbreviation for "power of hydrogen" [2].

--Bruce Stallsmith
Huntsville, AL, US of A
where English is still the language of instruction

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