phenolphthalein

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

noun

Chemistry, Pharmacology.

1. 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- /

noun

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

phenolphthalein

1. 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 .

Word History and Origins

Origin of phenolphthalein¹

First recorded in 1870–75; phenol + phthalein

Example Sentences

Still other dietary supplement products for weight loss contained the laxative phenolphthalein or prescription diuretics.

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A chemical called phenolphthalein -- not approved by FDA -- was found in a Chinese product called Zi Xiu Tang Beauty Face & Figure Capsule.

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Some of the supplements also contain another chemical used previously in over-the-counter laxative products, a dye called phenolphthalein.

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Add 50 to 100 cc. hot, neutral alcohol, and titrate with N/2, N/4 or N/10 sodium hydroxide depending on the fatty acid content, using phenolphthalein as indicator.

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Titrate the distillate with N/10 alkali, using phenolphthalein as an indicator.

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