Search results
Results from the WOW.Com Content Network
Phenolphthalein (/ f ɛ ˈ n ɒ l (f) θ ə l iː n / [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.
The two electrons are supplied by phenolphthalein: HOOH + 2 e − + 2 H + → 2 H 2 O. The consumption of protons during the course of the reaction has the effect of raising the pH of the solution, but the amount of base produced is negligible compared to the amount of base already present in the reagent mixture.
Animation of a strong acid–strong base neutralization titration (using phenolphthalein).The equivalence point is marked in red. In chemistry, neutralization or neutralisation (see spelling differences) is a chemical reaction in which acid and a base react with an equivalent quantity of each other.
A strong base is a basic chemical compound that can remove a proton (H +) from (or deprotonate) a molecule of even a very weak acid (such as water) in an acid–base reaction. Common examples of strong bases include hydroxides of alkali metals and alkaline earth metals, like NaOH and Ca(OH)
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. Common phthalein dyes include ...
In reaction depicted below 3,4,5-trimethylphenol reacts with singlet oxygen generated from oxone/sodium carbonate in an acetonitrile/water mixture to a para-peroxyquinole. This hydroperoxide is reduced to the quinole with sodium thiosulfate. Phenols are oxidized to hydroquinones in the Elbs persulfate oxidation.
A Lewis base is also a Brønsted–Lowry base, but a Lewis acid does not need to be a Brønsted–Lowry acid. The classification into hard and soft acids and bases ( HSAB theory ) followed in 1963. The strength of Lewis acid-base interactions, as measured by the standard enthalpy of formation of an adduct can be predicted by the Drago–Wayland ...
A well-known application of this reactivity is the preparation of the anthraquinone dye quinizarin by reaction with para-chlorophenol followed by hydrolysis of the chloride. [7] Phenolphthalein can be synthesized by the condensation of phthalic anhydride with two equivalents of phenol under acidic conditions (hence