Question

Phenolphthalein gives a pink colour in alkaline medium due to the fact that:

• A. It is coloured compound
• B. It ionises to give coloured ions
• C. It is decomposed by alkali
• D. It forms a complex compound with alkali

Answer 1

The correct option is B It ionises to give coloured ions

Phenolphthalien itself weak acid form pink anions when it dissolves in water so it gives pink color in acidic medium.