In `S_(N^(1))` the first step involves the formation of

Options

A. free radical
B. carbanion
C. carbocations
D. final products

Answer

To solve the question regarding the first step of the SN1 reaction mechanism, we will break it down step by step.

### Step 1: Understanding the SN1 Mechanism
The SN1 (Substitution Nucleophilic Unimolecular) reaction mechanism consists of two main steps. The first step is crucial as it determines the rate of the reaction.

### Step 2: Identifying the First Step
In the first step of the SN1 mechanism, the alkyl halide undergoes ionization. This involves the breaking of the carbon-halogen bond, leading to the formation of a carbocation and a halide ion.

### Step 3: Formation of Carbocation
For example, if we consider a tertiary alkyl halide, the structure can be represented as follows:

```
CH3
|
R - C - X (where R is an alkyl group and X is the halogen)
|
CH3
```

Upon ionization, the bond between carbon (C) and the halogen (X) breaks, resulting in the formation of a tertiary carbocation (C⁺) and a halide ion (X⁻):

```
CH3
|
R - C⁺ + X⁻
|
CH3
```

This step is slow and is the rate-determining step of the reaction.

### Step 4: Conclusion
Thus, the first step of the SN1 reaction involves the formation of a carbocation. Therefore, the correct answer to the question is **carbocations**.

### Final Answer
The first step in the SN1 reaction involves the formation of **carbocations**.

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