Phenolphthalein indicator: Phenolphthalein is often used

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. It belongs to the class of dyes known as phthalein dyes. Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols in experiments. Phenolphthalein is an organic compound that serves as a laboratory reagent and pH indicator. It stimulates the intestinal mucosa and constricts smooth muscles, causing laxative effects. Learn about phenolphthalein its structure, formula, properties, colour change with pH, and wide applications in chemistry. Phenolphthalein is a pH indicator that changes from colorless to fuchsia pink as the pH increases. Learn how to make it, how it works, and what it is used for in chemistry and other fields.