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Phenolphthalein (/ fɛˈnɒl (f) θəliːn / [citation needed] feh-NOL (F)-thə-leen) is a chemical compound with the formula C 20 H 14 O 4 and is often written as " HIn ", " HPh ", " phph " or simply " Ph " in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless ...
A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH (acidity or basicity) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. [1] Hence, a pH indicator is a chemical detector for hydronium ions (H 3 O +) or hydrogen ions (H +) in the ...
Phthalein dye. Chemical structure of phenolphthalein, a common phthalein dye. Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH. [1] They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes.
Universal indicator. 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]
An acid–base titration is a method of quantitative analysis for determining the concentration of Brønsted-Lowry acid or base (titrate) by neutralizing it using a solution of known concentration (titrant). [1] A pH indicator is used to monitor the progress of the acid–base reaction and a titration curve can be constructed.
o-Cresolphthalein is a phthalein dye used as a pH indicator in titrations. It is insoluble in water but soluble in ethanol. Its solution is colourless below pH 8.2, and purple above 9.8. Its molecular formula is C 22 H 18 O 4.
The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin. It relies on the peroxidase -like activity of hemoglobin in blood to catalyze the oxidation of phenolphthalin (the colorless reduced form of phenolphthalein) into ...
Low does: eye and skin irritant High dose: rapid breathing, bluish discoloring of the skin, and fluid in the lungs Hydrogen cyanide Gas: colorless, or pale blue Odor: bitter almonds < 1 minute Hyperventilation, loss of consciousness, and convulsions Choking Agents Chlorine Gas: yellow-green Odor: bleach Seconds to minutes