Assertion (A) : Gabriel phthalimide reaction is used for the prepartion fo ` C_2H_5NH_2` and p-nitro aniline .
Reason (R ): `SN^2` reaction takes place with `1^@ RX` and `1^@ ArX` containing `overline e`- withdrawing group at o-and p-positions

Options

A. If both (A) and (R ) ar true, and (R ) is the correct explanation of (A).
B. If both (A) and (R ) are true , and (R ) is not the correct explanation of (A).
C. If (A) is true , but (R ) is false .
D. If both (A) and (R ) are false .

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states that the Gabriel phthalimide reaction is used for the preparation of C₂H₅NH₂ (ethylamine) and p-nitroaniline.

- **Gabriel Phthalimide Reaction**: This reaction involves the use of phthalimide, which is a cyclic imide. It reacts with a base to form a nucleophilic species that can attack an alkyl halide to form a primary amine.

### Step 2: Preparation of C₂H₅NH₂
1. **Start with Phthalimide**: The structure of phthalimide is C₆H₄(CO)₂NH.
2. **Deprotonation**: Treat phthalimide with a strong base (like KOH) to deprotonate the NH group, forming a phthalimide anion.
3. **SN2 Reaction**: The phthalimide anion can then undergo an SN2 reaction with ethyl iodide (C₂H₅I). The nucleophilic nitrogen attacks the carbon of the ethyl halide, leading to the formation of N-ethylphthalimide.
4. **Hydrolysis**: Finally, hydrolyze the N-ethylphthalimide to yield ethylamine (C₂H₅NH₂) and phthalic acid.

### Step 3: Preparation of p-Nitroaniline
1. **Starting Material**: Again, start with phthalimide.
2. **Deprotonation**: Treat with a base to form the phthalimide anion.
3. **SN2 Reaction with p-Nitroethyl Halide**: Use a p-nitro substituted alkyl halide (like p-nitroethyl bromide) for the SN2 reaction. The electron-withdrawing nitro group facilitates the nucleophilic attack.
4. **Hydrolysis**: Hydrolyze the product to yield p-nitroaniline.

### Step 4: Understanding the Reason
The reason states that SN2 reactions take place with primary alkyl halides (1° RX) and aryl halides (1° ArX) containing electron-withdrawing groups at the ortho and para positions.

- **SN2 Mechanism**: The SN2 mechanism is favored for primary substrates because steric hindrance is minimal, allowing the nucleophile to effectively attack the electrophilic carbon.
- **Electron-Withdrawing Groups**: The presence of electron-withdrawing groups (like nitro) at the ortho or para positions on the aryl halide stabilizes the transition state and enhances the nucleophilicity of the attacking species.

### Conclusion
Both the assertion and the reason are true. The reason correctly explains why the assertion is valid.

### Final Answer
- **Assertion (A)**: True
- **Reason (R)**: True
- **Explanation**: The reason is a correct explanation of the assertion.

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