phenolphthalein

American  

[fee-nawl-thal-een, -ee-in, -fthal-, -nol-] / ˌfi nɔlˈθæl in, -i ɪn, -ˈfθæl-, -nɒl- /

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.

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phenolphthalein British  

/ -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

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phenolphthalein Scientific  

/ fē′nōl-thăl′ēn′ /

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 .

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Etymology

Origin of phenolphthalein

First recorded in 1870–75; phenol + phthalein

Example Sentences

Any of the three indicators will exhibit a reasonably sharp color change at the equivalence point of the strong acid titration, but only phenolphthalein is suitable for use in the weak acid titration.

From Textbooks • Feb. 14, 2019

Substances such as phenolphthalein, which can be used to determine the pH of a solution, are called acid-base indicators.

From Textbooks • Feb. 14, 2019

If the mucous lining of the intestinal tract is in the least eroded, the phenolphthalein quickly seeps into the blood stream.*

From Time Magazine Archive

The harmlessly adulterated blood in due course swishes through the kidneys, leaving a residue of phenolphthalein to trickle into the bladder with the urine.

From Time Magazine Archive

If borax is present the carbon dioxide is boiled off after neutralizing exactly to methyl orange; cool, add mannite and phenolphthalein and titrate the boric acid with standard alkali.

From Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. by Thomssen, E. G.