Butane nitrile can be prepared by heating

Options

A. propyl chloride with alc. KCN
B. butyl chloride with alc. KCN
C. propyl chloride with alc. AgCN
D. butyl chloride with alc. AgCN

Answer

To prepare butane nitrile, we can use the following steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: We need to prepare butane nitrile (C₄H₉CN). The starting material is propyl chloride (C₃H₇Cl), which has three carbon atoms.

2. **Choose the Nucleophile**: The nucleophile we can use is potassium cyanide (KCN). KCN consists of K⁺ and CN⁻ ions, where CN⁻ acts as the nucleophile.

3. **Nucleophilic Substitution Reaction**: In the presence of KCN, the CN⁻ ion will attack the electrophilic carbon atom in propyl chloride. The chlorine atom (Cl) is a good leaving group due to its ability to stabilize the negative charge after leaving.

4. **Mechanism of the Reaction**:
- The nucleophile (CN⁻) attacks the carbon atom bonded to the chlorine in propyl chloride.
- This results in the displacement of the chlorine atom, forming butane nitrile (C₄H₉CN).

5. **Final Product**: The product of this reaction is butane nitrile, which has the structure CH₃-CH₂-CH₂-C≡N.

### Conclusion:
The correct option for preparing butane nitrile by heating is **Option A**, which involves the reaction of propyl chloride with KCN.

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