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The following other wikis use this file: Usage on bg.wikipedia.org Водороден показател; Usage on en.wikibooks.org Principles of Biochemistry/Water: The solvent of the cell
A universal indicator is a pH indicator made of a solution of several compounds that exhibit various smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. A universal indicator can be in paper form or present in a form of a solution. [1]
The pH value of a neutral solution is 7.0 at 25°C (standard laboratory conditions). Solutions with a pH value below 7.0 are considered acidic and solutions with pH value above 7.0 are basic. Solutions with a pH value below 7.0 are considered acidic and solutions with pH value above 7.0 are basic.
The pH range is commonly given as zero to 14, but a pH value can be less than 0 for very concentrated strong acids or greater than 14 for very concentrated strong bases. [2] The pH scale is traceable to a set of standard solutions whose pH is established by international agreement. [3]
English: I retrieved the soil pH maps from . In GIMP 2.4.3 I used the "Select by Color Tool" (threshold 15.0) to create pH-specific maps. Note that the original maps do not indicate actual pH values in the pH scale. For soils with acidic pH, I included the colors indicated by the leftmost 14 bars in the pH scale, ranging from red to pink.
The calibration process correlates the voltage produced by the probe (approximately 0.06 volts per pH unit) with the pH scale. Good laboratory practice dictates that, after each measurement, the probes are rinsed with distilled water or deionized water to remove any traces of the solution being measured, blotted with a scientific wipe to absorb ...
The pH scale is by far the most commonly used acidity function, and is ideal for dilute aqueous solutions. Other acidity functions have been proposed for different environments, most notably the Hammett acidity function , H 0 , [ 3 ] for superacid media and its modified version H − for superbasic media.
The Hammett acidity function (H 0) is a measure of acidity that is used for very concentrated solutions of strong acids, including superacids.It was proposed by the physical organic chemist Louis Plack Hammett [1] [2] and is the best-known acidity function used to extend the measure of Brønsted–Lowry acidity beyond the dilute aqueous solutions for which the pH scale is useful.