HCl + C20H14O4 → NaCl + H2O + C20H12O4
In this reaction, hydrochloric acid donates a hydrogen ion (H+) to phenolphthalein, which acts as a base and accepts the hydrogen ion. The products of the reaction are sodium chloride (NaCl), water (H2O), and phenolphthalein in its acid form (C20H12O4).
Phenolphthalein is commonly used as an indicator in acid-base titrations because it undergoes a color change at a specific pH range. In acidic solutions, phenolphthalein is colorless, while in basic solutions, it turns pink. The endpoint of the titration is reached when the solution turns pink, indicating that all of the hydrochloric acid has been neutralized by the phenolphthalein.
