1-Bromopentane is more reactive towards

Options

A. `S_N2` and `S_N1`
B. `S_N1` and `S_N2`
C. Both `S_N1`
D. Both `S_N2`

Answer

To determine the reactivity of 1-bromopentane towards different nucleophilic substitution mechanisms, we need to analyze its structure and the characteristics of the mechanisms involved.

### Step-by-Step Solution:

1. **Identify the Structure of 1-Bromopentane**:
- 1-bromopentane is a straight-chain alkane with a bromine atom attached to the first carbon. Its chemical structure can be represented as CH3-CH2-CH2-CH2-Br.

2. **Determine the Type of Halide**:
- The bromine atom is attached to a primary carbon (the first carbon in the chain), making 1-bromopentane a primary alkyl halide.

3. **Understand SN1 and SN2 Mechanisms**:
- **SN1 Mechanism**: This is a two-step mechanism where the first step involves the formation of a carbocation. It is favored by tertiary and some secondary alkyl halides due to the stability of the carbocation formed.
- **SN2 Mechanism**: This is a one-step mechanism where the nucleophile attacks the carbon atom simultaneously as the leaving group (bromine) departs. It is favored by primary alkyl halides because they do not form stable carbocations.

4. **Analyze the Reactivity of 1-Bromopentane**:
- Since 1-bromopentane is a primary halide, it is more likely to undergo the SN2 mechanism rather than SN1. The steric hindrance is low, allowing the nucleophile to attack the carbon atom effectively.

5. **Conclusion**:
- Therefore, 1-bromopentane is more reactive towards the SN2 mechanism.

### Final Answer:
1-bromopentane is more reactive towards the SN2 mechanism.

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