PHTHALEIN

Noun

phthalein (plural phthaleins)

(organic compound) any of a range of lactones formed by the reaction of phenols with phthalic anhydride

Source: Wiktionary


Phthal"e*in, n. Etym: [See Phthalic.] (Chem.)

Definition: One of a series of artificial organic dyes made as condensation products of the phenols with phthalic acid, and well represented by phenol phthaleïn. 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.

Source: Webster’s Unabridged Dictionary 1913 Edition



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Word of the Day

21 April 2025

ENCYCLOPEDIA

(noun) a reference work (often in several volumes) containing articles on various topics (often arranged in alphabetical order) dealing with the entire range of human knowledge or with some particular specialty


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