phenolphthalein

[ fee-nawl-thal-een, -ee-in, -fthal-, -nol- ]

Phonetic (Standard)IPA

noun

, Chemistry, Pharmacology.

a white, crystalline compound, C 2 0 H 1 4 O 4 , used as an indicator in acid-base titration and as a laxative.

phenolphthalein

/ -lɪɪn; ˌfiːnɒlˈθeɪliːn; -ˈθæl- /

a colourless crystalline compound used in medicine as a laxative and in chemistry as an indicator. Formula: C 20 H 14 O 4

phenolphthalein

/ fē′nōl-thăl′ēn′ /

A white or pale-yellow, crystalline powder used as an indicator for acid and basic solutions. In solutions that are either neutral or basic, it is colorless, while it is pink or red in solutions that are alkali. It is also used as a laxative and in making dyes. Chemical formula: C 20 H 14 O 4 .

First recorded in 1870–75; phenol + phthalein

It is undoubtedly true, however, as we have previously stated, that phenolphthalein is worthy of a trial.

The first page mentioned discusses the introduction of phenolphthalein into medicine.

Then boil for two minutes, neutralize exactly with dilute acetic acid (use phenolphthalein as the indicator).

Mould growth, on the other hand, is most vigourous in media that are strongly acid to phenolphthalein.

Litmus is insensitive to many weak organic acids the presence of which is readily indicated by phenolphthalein.

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