pH

pH

noun \ˈpē-ˈāch\

Definition of PH

: a measure of acidity and alkalinity of a solution that is a number on a scale on which a value of 7 represents neutrality and lower numbers indicate increasing acidity and higher numbers increasing alkalinity and on which each unit of change represents a tenfold change in acidity or alkalinity and that is the negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity in gram equivalents per liter of the solution; also : the condition represented by a pH number

Origin of PH

German, from Potenz power + H (symbol for hydrogen)

First Known Use: 1909

PH

abbreviation

Definition of PH

1

pinch hit

2

public health

3

Purple Heart

pH

noun \(ˈ)pē-ˈāch\   (Medical Dictionary)

Medical Definition of PH

: a measure of acidity and alkalinity of a solution that is a number on a scale on which a value of 7 represents neutrality and lower numbers indicate increasing acidity and higher numbers increasing alkalinity and on which each unit of change represents a tenfold change in acidity or alkalinity and that is the negative logarithm of the effective hydrogen-ion concentration or hydrogen-ion activity in gram equivalents per liter of the solution <instead of saying that the concentration of hydrogen ion in pure water is 1.00 x 10⁻⁷, it is customary to say that the pH of pure water is 7—Linus Pauling>; also : the condition represented by such a number—compare pk

pH

noun    (Concise Encyclopedia)

Quantitative measure of the strength of the acidity or alkalinity (see acid; base) of a solution. It is defined as the negative common logarithm of the concentration of hydrogen ions [H⁺] in moles/litre: pH = log [H⁺]. The letters of its name are derived from the absolute value of the power (p) of the hydrogen ion concentration (H). The product of the concentrations in water of H⁺ and OH (the hydroxide ion) is always about 10¹⁴. The strongest acid solution has more than 1 mole/litre of H⁺ (and about 10¹⁴ of OH), for a pH of less than 0. The strongest basic solution has about 10¹⁴ mole/litre of H⁺ (and about 1 of OH), for a pH of 14. A neutral solution has about 10⁷ mole/litre of both H⁺ and OH, for a pH of 7. The pH value, measured by a pH meter, titration, or indicator (e.g., litmus) strips, helps inform chemists of the nature, composition, or extent of reaction of substances, biologists of the composition and environment of organisms or their parts or fluids, physicians of the functioning of bodily systems, and agronomists of the suitability of soils for crops and any treatments needed. The pH is now defined in electrochemical terms (see electrochemistry).