Question

When phenol reacts with phthalic anhydride in presence of $H _{2} SO _{4}$ and heated and hot reaction mixture is poured in $NaOH$ solution, then product formed is

• A. alizarin
• B. methyl orange
• C. fluorescein
• D. phenolphthalein

Answer 1

Answer: (D)

phenolphthalein

Answer 2

Phenol couples with phthalic anhydride in presence of cone. HSO to form phenolphthalein which is used as an indicator :