fenoliftaliinia

Fenolftaleina is a chemical compound with the formula C20H14O4. It is an organic compound belonging to the phthalein dye family. Fenolftaleina is synthesized by the reaction of phenol with phthalic anhydride in the presence of an acid catalyst such as concentrated sulfuric acid or zinc chloride. It typically appears as a white to yellowish-white crystalline powder.

The most well-known property of fenolftaleina is its use as a pH indicator. In acidic solutions, fenolftaleina is colorless. As the pH increases and becomes alkaline (basic), it undergoes a structural change and turns pink or fuchsia. This color change occurs within a pH range of approximately 8.2 to 10.0. Due to this characteristic, it is widely used in titrations to determine the endpoint of acid-base reactions.

Beyond its indicator properties, fenolftaleina has also been used historically as a laxative. However, concerns about its safety and potential carcinogenicity have led to its withdrawal from over-the-counter laxative products in many countries. It is still employed in some scientific and educational contexts for demonstrations of acid-base chemistry. The compound's synthesis and properties are studied in organic chemistry laboratories.