What happens when 2 moles of phenol reacts with phthalic anhydride in presence of anhydrous ZnCl₂?

Phenolphthalein is formed

The correct answer is option 2.  Phenolphthalein is formed.

When 2 moles of phenol react with phthalic anhydride in the presence of anhydrous \(ZnCl_2\), the product formed is Phenolphthalein.

The reaction involves a condensation process between the two aromatic rings. Anhydrous \(ZnCl_2\) acts as a Lewis acid catalyst, facilitating the reaction by accepting a lone pair of electrons from the carbonyl oxygen \((C=O)\) of the phthalic anhydride. Each phenol molecule reacts with one carbonyl group of the anhydride, eliminating a water molecule \((H_2O)\) in the process. The two phenol rings become linked through a carbon-carbon bond, forming the core structure of phenolphthalein. Therefore, under these specific conditions (2 moles phenol, phthalic anhydride, and \(ZnCl_2\) catalyst), phenolphthalein is the primary product.

Here is why the other options are not correct:

Quinonoid: Quinonoids are cyclic structures formed by the oxidation of certain aromatic compounds. This reaction doesn't involve oxidation.

Benzenoid: Benzenoid refers to aromatic compounds with a structure similar to benzene. Phenol and phthalic anhydride are already benzenoid compounds, and the reaction doesn't change their basic structure.

Fluorescein: Fluorescein is another product obtained from the reaction of phenol with phthalic anhydride, but it requires specific conditions and a different catalyst. This reaction typically uses concentrated sulfuric acid \((H_2SO_4)\) as a catalyst.