Ph

pH
pH is a measure of the concentration of protons (H+) in a solution and, in effect, its acidity or alkalinity. The p stands for the German "Potenz", meaning power or concentration, and the H for the hydrogen ion (H+).

pH (abbr. power of hydrogen [2]) 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.

pH Scale
The pH scale is used to measure the amount of acid in a substance. The lower the number, the higher the amount of acid. Rain below pH 5 is said to be "acid rain".

pH: Numeric value that describes the intensity of the acid or basic (alkaline) conditions of a solution. The ph scale is from 0 to 14, with the neutral point at 7.0. Values lower than 7 indicate the presence of acids and greater than 7.

pH
a logarithmic scale (0-14) that reflects acidity or alkalinity; pH 7 indicates neutrality; acidic solutions have lower pH values; alkaline solutions have higher values ...

pH-dependent cation exchange capacity
The difference between the effective cation exchange capacity and the cation exchange capacity of a soil measured at a pH higher than that of its natural value.
phase (soil) ...

pH: An expression of the intensity of the basic or acid condition of a liquid; may range from 0 to 14, where 0 is the most acid and 7 is neutral. Natural waters usually have a pH between 6.5 and 8.5.

pH - The negative logarithm of the hydrogen ion concentration of a solution. It is the quantitative expression of the acidity and alkalinity of a solution and has a scale that generally ranges from about 0 to 14.

pH (power hydrogen) The negative logarith of hydrogen-ion concentration to measure the acidity or alkalinity of a liquid or solid material. The range of pH goes from 0 to 14 where 0 is most acid and 14 most basic and 7 neutral.

pH: An expression of both acidity and alkalinity on a scale of zero to 14, with seven representing neutrality; numbers less than seven indicate increasing acidity and numbers greater than seven indicate increasing alkalinity.

pH: numerical measure of acidity, with a scale of 0 to 14. Neutral is pH 7, values below 7 are acidic, and values above 7 are alkaline.

pH
the negative logarithm of the hydrogen ion concentration (-log10[H+]) where H+ is the hydrogen-ion concentration in moles per liter. Neutral water has a pH value of 7.
pH adjustment ...

pH
A convenient way of describing the strength of an acidic or basic aqueous solution. The values range from 0 to 14, with a pH of 7 corresponding to neutral.

pH is the scale for all liquid chemicals. Acids and alkalis are the chemicals at each end of the pH spectrum. The scale runs from 0 (acid) to 14 (alkali).

pH (pronounce as separate letters). pH is an expression of the intensity of the basic or acid condition of a liquid. Mathematically, pH is the logarithm (base 10) of the reciprocal of the hydrogen ion concentration, [H+].

pH : A measure of the acidity of a solution. pH is equal to the negative logarithm of the concentration of hydrogen ions in a solution. A pH of 7 is neutral. Values less than 7 are acidic, and values greater than 7 are basic.

pH
The value that determines if a substance is acid, neutral or basic, calculated from the number of hydrogen ions present. It is measured on a scale from 0 to 14, on which 7 means the substance is neutral.

pH: Measure of acidity. Stands for Òthe negative logarithm of free hydrogen ionsÓ in water. Water of low pH is acidic; high pH is basic, or alkaline.
Point Source: A pipe that discharges effluent into a stream or other body of water.

pH
The measure of acidity or alkalinity of a chemical solution, from 014. Anything neutral, for example, has a pH of 7. Acids have a pH less than 7, bases (alkaline) greater than 7.

acid rain Precipitation which has a pH of less than 5.6. acute toxicity Any poisonous effect produced within a short period of time, resulting in severe biological harm and often death.

acid precipitation air pollution consisting of all forms of precipitation, including wet and dry particles, that have an acidity lower than normal rainfall (pH 5.6).
acid rain. See acid precipitation.

Soil acidity (or pH) is defined as the logarithm of the reciprocal of the Hydrogen ion (H+) activity or pH = -log Activity H+, but in practice this equation is usually circumvented by the use of a soil pH meter.

one that readily ionizes in aqueous solution to yield OH anions, with a pH above 7.0, and turns litmus paper blue. Examples are oxides and hydroxides of certain metals belonging to group IA of the periodic table (Li, Na, K, Rb, Cs, Fr).

Acid - A material with pH of less than 7.0.
Acute Exposure - A single exposure to a toxic substance which results in severe biological harm or death.

pH = pKa - lg([HA]/[A-])
for the calculation of the pH of solutions where the ratio [HA]/[A-] is known and HA and A- are the hydronated and dehydronated forms of an acid, respectively.
Corrected from [3] ...

Acid Rain: Rain which is especially acidic (pH <5.2). Principal components of acid rain typically include nitric and sulfuric acid. These may be formed by the combination of nitrogen and sulfur oxides with water vapor in the atmosphere.

The alkalinity in a water sample measured by the amount of standard acid needed to lower the pH to a level of 8.3 as indicated by the change of color of the phenolphthalein from pink to clear.
Source: Terms of the Environment
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A corrosive solution with a pH less than 7.
Acid Aerosol
Acidic liquid or solid particles small enough to become airborne. High concentrations can irritate the lungs and have been associated with respiratory diseases like asthma.

Acid Neutralizing Capacity- Measure of ability of a base (e.g. water or soil) to resist changes in pH.
Acidic- The condition of water or soil that contains a sufficient amount of acid substances to lower the pH below 7.0.

Corrosive waste A waste that is outside the pH range of 2 to 12.5 or a waste that corrodes steel at a rate greater than 6.35 mm (0.25 in) per year. One of EPA's four hazardous waste properties.
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Buffer Action: A substance's resistance to a change in pH.
Building Envelope: Elements of the building, including all external building materials, windows, and walls, that enclose the internal space.

Langelier Index (LI): An index reflecting the equilibrium pH of a water with respect to calcium and alkalinity; used in stabilizing water to control both corrosion and scale deposition.

Alkali a classification of substances that liberate hydroxide ions in water, to form caustic and corrosive solutions which turn litmus paper blue, with a pH higher than 7, for example sodium Hydroxide.

Alkalosis-Pathological condition in which the hydrogen ion substance concentration of body fluids is below normal and hence the pH of blood rises above the reference interval. (IUPAC) ...

and planted as ‘shade gardens' in lieu of traditional lawns." Moss plants do not possess true roots, he points out, instead deriving their nutrients and moisture from the air. As such they like wet surroundings and also soil with a pH that is ...

See also: Water, Soil, Environment, Condition, Air