Phenolphthalein is a common pH indicator used in acid-base chemistry. But the history behind this compound is stranger than fiction! It was originally developed as a synthetic dye to compete with mauvine in the late 19th century. It was never used as a dye due to its pH sensitivity, which led to widespread use as a pH indicator. Phenolphthalein will change from colorless to pink once the pH is above 8, making it an ideal indicator for acid-base titrations. This color changing property also led t