Gabriel synthesis is used for the preparation of primary amines. Phthalimide on treatment with ethanolic potassium hydroxide forms potassium salt of phthalimide which on heating with alkyl halide followed by alkaline hydrolysis produces the corresponding primary amine. Aromatic primary amines cannot be prepared by this method because aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.

What is the product formed when N-Methylphthalimide undergoes acid hydrolysis? 

Phthalic acid 

The correct answer is option 1. Phthalic acid.

When N-Methylphthalimide undergoes acid hydrolysis, the product formed is phthalic acid. This reaction also releases methylamine as a byproduct. The acid hydrolysis of N-Methylphthalimide involves breaking the amide bond, leading to the formation of phthalic acid.

N-Methylphthalimide is hydrolyzed in the presence of an acid. The amide bond is cleaved, releasing phthalic acid and methylamine.

The overall reaction can be represented as follows:

The product of the acid hydrolysis of N-Methylphthalimide is phthalic acid.

Therefore, the correct answer is Phthalic acid.