Question

Why phenolphthalein disapperas in highly alkaline solution?

Answer 1

Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colourless in acidic solutions and magenta in basic solutions. ... It is a weak acid, which can lose H+ ions in solution.

Solubility in water: 400 mg/L in water

Solubility in other solvents: Insoluble in benzene or hexane, very soluble in ethanol ...