Complete the following statements by selecting the correct alternative from the choices given :
During the course of an `S_(N)l` reaction, the intermediate species formed is :

Options

A. a carbocation
B. a free radical
C. a carbanion
D. an intermediate complex

Explanation

To solve the question regarding the intermediate species formed during an SN1 reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding SN1 Reaction Mechanism**:
- The SN1 (Substitution Nucleophilic Unimolecular) reaction occurs in two main steps. The first step involves the formation of a carbocation, which is a positively charged carbon species.

2. **Identifying the Rate-Determining Step**:
- The first step of the SN1 reaction is the slowest and is known as the rate-determining step. This step involves the leaving group departing and forming the carbocation.

3. **Formation of the Carbocation**:
- For example, in the case of tertiary butyl bromide, the bromide ion (Br-) acts as the leaving group. When it leaves, it creates a tertiary carbocation. This is crucial because the stability of the carbocation influences the rate of the reaction.

4. **Attack of the Nucleophile**:
- In the second step, a nucleophile attacks the carbocation, leading to the formation of the final product. However, the intermediate species formed during the first step is the carbocation.

5. **Conclusion**:
- Therefore, the intermediate species formed during the course of an SN1 reaction is a **carbocation**.

### Final Answer:
The correct alternative is: **Carbocation**.

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