What is "phenol phthalein"

Phenolphthalein \Phe`nol*phthal"e*in\, n., or Phenol phthalein \Phenol phthalein\(Chem.) A white or yellowish white crystalline substance, C20H14O4, formed by condensation of the anhydride of phthalic acid and phenol. Its solution in alkalies is brilliant red, but is decolorized by acids. This reaction, being very delicate, is used as an indicator. It is sometimes used as a laxative in veterinary medicine.

Phthalein \Phthal"e*in\, n. [See Phthalic.] (Chem.) One of a series of artificial organic dyes made as condensation products of the phenols with phthalic acid, and well represented by phenol phthale["i]n. Their alkaline solutions are fluorescent.

Phenol phthalein, a white or yellowish white crystalline substance made from phthalic acid and phenol. Its solution in alkalies is brilliant red, but is decolorized by acids, and as this reaction is exceedingly delicate it is used as an indicator.

Phenol \Phe"nol\, n. [Gr. ? to show + -ol: cf. F. ph['e]nol.] (Chem.)

1. A white or pinkish crystalline substance, C6H5OH, produced by the destructive distillation of many organic bodies, as wood, coal, etc., and obtained from the heavy oil from coal tar.

   Note: It has a peculiar odor, somewhat resembling creosote, which is a complex mixture of phenol derivatives. It is of the type of alcohols, and is called also phenyl alcohol, but has acid properties, and hence is popularly called carbolic acid, and was formerly called phenic acid. It is a powerful caustic poison, and in dilute solution has been used as an antiseptic.

2. Any one of the series of hydroxyl derivatives of which phenol proper is the type.

   Glacial phenol (Chem.), pure crystallized phenol or carbolic acid.

   Phenol acid (Chem.), any one of a series of compounds which are at once derivatives of both phenol and some member of the fatty acid series; thus, salicylic acid is a phenol acid.

   Phenol alcohol (Chem.), any one of series of derivatives of phenol and carbinol which have the properties of both combined; thus, saligenin is a phenol alcohol.

   Phenol aldehyde (Chem.), any one of a series of compounds having both phenol and aldehyde properties.

   Phenol phthalein. See under Phthalein.

n. (context chemistry English) A white or yellowish-white crystalline substance made from phthalic acid and phenol. Its solution in alkalis is brilliant red, but is decolorized by acids, and as this reaction is exceedingly delicate it is used as an indicator.