Phenolphthalein, an organic phthalein compound widely used as an acid-base indicator. As an indicator of the pH of a solution, phenolphthalein is colorless below pH 8.5 and pink to dark red above pH 9.0.

What are the uses of phenolphthalein?

A popular application of phenolphthalein is as an indicator in acid-base titrations. Phenolphthalein is somewhat water soluble and is usually dissolved in alcohol for experimental use. It is a weak acid that loses H+ ions in solution. Phenolphthalein molecules are colorless, and phenolphthalein ions are purple.

Is phenolphthalein acidic or basic?

Phenolphthalein is an organic compound with the chemical formula C20H14O4, which is a weak acid and can be used as an indicator for acid-base titration. In acidic solution, this compound is colorless. It is pink in simple solution (transition occurs around pH 9).

How does phenolphthalein work as an indicator?

Phenolphthalein is a colorless weak acid, which is widely used as an indicator to indicate the end point of titration in titration experiments. The endpoint is indicated by the formation of a pink color because the compound dissociates to form a pink anion when dissolved in water.

What color is phenolphthalein?

Phenolphthalein is a white or colorless compound.

Phenolphthalein is a strong laxative that works within 6-8 hours; its effects may last 3-4 days. Adverse reactions such as kidney irritation or rash may occur. Phenolphthalein was once widely used in over-the-counter laxatives, but its use in such drugs was banned by the U.S. Food and Drug Administration in 1999 because animal studies showed it could cause cancer in humans.

Phenolphthalein, which is closely related to triphenylmethane dyes, was prepared in 1871 by German chemist Adolf von Bayer by melting phenol and phthalic anhydride in the presence of sulfuric acid or zinc chloride, and it is still used today.