Most reactive halide towards `S_(N^(1))` reactions is

Options

A. n-Butyl chloride
B. sec-Butyl chloride
C. tert-Butyl chloride
D. All chloride

Explanation

To determine the most reactive halide towards SN1 reactions, we need to analyze the stability of the carbocations formed during the reaction mechanism. The SN1 (Unimolecular Nucleophilic Substitution) reaction proceeds through two main steps:

### Step 1: Understanding the SN1 Mechanism
1. **Formation of Carbocation**: The first step involves the departure of the leaving group (the halide), resulting in the formation of a carbocation. The stability of this carbocation is crucial for the reactivity of the halide.

2. **Nucleophilic Attack**: In the second step, a nucleophile attacks the carbocation, leading to the formation of the final product.

### Step 2: Carbocation Stability
- The stability of carbocations follows a specific order:
- Tertiary (3°) carbocation > Secondary (2°) carbocation > Primary (1°) carbocation > Methyl carbocation.

- Tertiary carbocations are the most stable due to the inductive effect and hyperconjugation from the surrounding alkyl groups.

### Step 3: Analyzing Halides
- When considering halides, we look at the type of halide that can form the most stable carbocation upon leaving:
- **Tertiary Halides**: These will form tertiary carbocations, which are the most stable and thus the most reactive in SN1 reactions.
- **Secondary Halides**: These will form secondary carbocations, which are less stable than tertiary.
- **Primary Halides**: These will form primary carbocations, which are the least stable.

### Step 4: Conclusion
- Among the halides, the tertiary halide (such as tertiary butyl chloride) will be the most reactive towards SN1 reactions because it leads to the formation of the most stable carbocation.

### Final Answer
**The most reactive halide towards SN1 reactions is a tertiary halide (e.g., tertiary butyl chloride).**

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