An acid-base indicator. Changes colour from clear and colourless in acid to pink in base over the pH range of 8.0 to 9.6.

-adapted from Quantitative Chemical Analysis, by Daniel C. Harris

Also is a VERY strong laxative. Used to be the main ingredient in a well known over-the-counter laxative until people complained it was too harsh.

I have it under good authority that the addition of small (and I do mean SMALL) amounts of phenolphthalein to a batch of oatmeal raisin cookies adds a slight flavour of licorice.

This node is for information only. Wash your hands, sit up straight, do your homework and pull up your pants

Phe`nol*phthal"e*in (?), n., or Phenol phthalein. (Chem.)

A white or yellowish white crystalline substance, C20H14O4, formed by condensation of the anhydride of phthalic acid and phenol. Its solution in alkalies is brilliant red, but is decolorized by acids. This reaction, being very delicate, is used as an indicator.


© Webster 1913

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