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phenolphthalein

phenolphthalein (fē´nôlthăl´ēən), or 2,2-Bis(p-hydroxyphenyl) phthalide, C20H14O4, crystalline organic compound. It is used medicinally as a laxative and is widely employed in the laboratory as an indicator of the acidity or basicity of solutions. In pure water it is insoluble, but it is soluble in basic solutions or in ethanol or acetone. In a solution with pH greater than 8 (pH 8 is mildly basic) phenolphthalein is pink to red in color, but at pH less than 8 it is colorless. Phenolphthalein is a phenol derivative of phthalic anhydride.

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"phenolphthalein." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 26 Jul. 2017 <http://www.encyclopedia.com>.

"phenolphthalein." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (July 26, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/phenolphthalein

"phenolphthalein." The Columbia Encyclopedia, 6th ed.. . Retrieved July 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/phenolphthalein

phenolphthalein

phenolphthalein A dye used as an acid-base indicator. It is colourless below pH 8 and red above pH 9.6. It is used in titrations involving weak acids and strong bases. It is also used as a laxative.

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"phenolphthalein." A Dictionary of Biology. . Encyclopedia.com. 26 Jul. 2017 <http://www.encyclopedia.com>.

"phenolphthalein." A Dictionary of Biology. . Encyclopedia.com. (July 26, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/phenolphthalein

"phenolphthalein." A Dictionary of Biology. . Retrieved July 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/phenolphthalein