Aromatic nitriles(ArCN) are not prepared by reaction:

Options

A. Ar X+KCN
B. `ArN_(2)^(+)Cl^(-)+CuCN`
C. `ArCONH_(2)+P_(2)O_(5)`
D. `ArCONH_(2)+SOCl_(2)`

Explanation

To determine which reaction does not produce aromatic nitriles (ArCN), we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Option 1: Aryl Halide + KCN**
- In this reaction, an aryl halide (ArX) is treated with potassium cyanide (KCN).
- Aryl halides exhibit a strong electron-withdrawing effect due to the halogen atom, which has both inductive (+I) and resonance (+M) effects.
- The presence of the halogen makes the aromatic ring less reactive towards nucleophilic substitution.
- Therefore, the cyanide ion (CN⁻) cannot effectively substitute the halogen in the aryl halide.
- **Conclusion**: This reaction does not produce aromatic nitriles (ArCN).

2. **Option 2: Aryl Diazonium Salt + CuCN**
- Here, an aryl diazonium salt (ArN₂⁺) reacts with copper(I) cyanide (CuCN).
- The diazonium group (N₂⁺) is a good leaving group and can be replaced by the cyanide ion.
- The reaction proceeds to yield aromatic nitrile (ArCN) and nitrogen gas (N₂).
- **Conclusion**: This reaction produces aromatic nitriles.

3. **Option 3: ArCONH₂ + P₂O₅**
- In this reaction, an amide (ArCONH₂) is treated with phosphorus pentoxide (P₂O₅).
- P₂O₅ acts as a dehydrating agent, facilitating the removal of water (H₂O) from the amide.
- The reaction leads to the formation of an aromatic nitrile (ArCN).
- **Conclusion**: This reaction produces aromatic nitriles.

4. **Option 4: ArCONH₂ + SOCl₂**
- In this case, the amide (ArCONH₂) is reacted with thionyl chloride (SOCl₂).
- The reaction results in the conversion of the amide to an aromatic nitrile (ArCN) along with the release of sulfur dioxide (SO₂) and hydrochloric acid (HCl).
- **Conclusion**: This reaction also produces aromatic nitriles.

### Final Answer:
The reaction that does not produce aromatic nitriles (ArCN) is **Option 1: Aryl Halide + KCN**.

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