PH

pH is a measure of the activity of hydrogen ions (H+) in a solution and, therefore, its acidity or alkalinity. In aqueous systems, the hydrogen ion activity is dictated by the dissociation constant of water (Kw) = 1.011 × 10−14 at 25 ?C) and interactions with other ions in solution. Due to this dissociation constant a neutral solution (hydrogen ion activity equals hydroxide ion activity) has a pH of approximately 7. Aqueous solutions with pH values lower than 7 are considered acidic, while pH values higher than 7 are considered alkaline.

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The concept was introduced by S.P.L. S?rensen in 1909. The p stands for the German Potenz, meaning power or potency, and the H for the hydrogen ion (H+). Sometimes it is referred as Latin pondus hydrogenii.

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Activity: Activity may refer to—...

Ion: : This article is about the electrically charged particle. For other uses of this word, see ion (disambiguation)....

Acidity: :For the condition of acidity, see acid....