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Chemical structure of phenolphthalein, a common phthalein dye
Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH.[1] They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes.
Common phthalein dyes include:
See also
References
