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.

Gabriel Phthalimide synthesis is used for the preparation of which amine? 

Primary aliphatic amine 

The correct answer is option 3. Primary aliphatic amine.

The Gabriel Phthalimide synthesis is a method specifically used for the preparation of primary aliphatic amines. This synthesis involves the use of phthalimide, which reacts with an alkyl halide to form N-alkylphthalimide. The N-alkylphthalimide is then hydrolyzed or treated with hydrazine to release the primary amine.

The steps are as follows:

1. Formation of N-alkylphthalimide:

\(\text{Phthalimide} + \text{R-X} \rightarrow \text{N-alkylphthalimide}\)

Where R is an alkyl group and X is a halogen (typically bromine or chlorine).

2. Hydrolysis or Reaction with Hydrazine:
\(\text{N-alkylphthalimide} + \text{H}_2\text{O} + \text{OH}^- \rightarrow \text{R-NH}_2 + \text{Phthalic Acid Salt}\)

Alternatively, hydrazine can be used to remove the phthalimide group and release the primary amine.

The Gabriel Phthalimide synthesis is a reliable method for synthesizing primary aliphatic amines, and it does not typically produce secondary, tertiary, or aromatic amines.

Therefore, the correct answer is Primary aliphatic amine.