Phenol is heated with pthalic anhydride in the presence of concentrated H₂SO₄.The product gives pink colour with alkali. The product is

Options

(a) salicylic acid
(b) bakelite
(c) phenolphthalein
(d) fluorescein

Correct Answer:

phenolphthalein

Explanation:

When phenol is heated with phthalic anhydride and a few drops of concentrated sulphuric acid (H₂SO₄) are added, phenolphthalein is formed. On adding excess of sodium hydroxide to this product, a pink colour is produced. This process is called phthalein fusion test.