For `S_(N)1` mechanism which of the following is correct ?

Options

A. Inversion (100 %)
B. Formation of carbocation
C. Non-polar solvent
D. Elimination

Answer

To solve the question regarding the characteristics of the \( S_N1 \) mechanism, we will analyze the key features of this mechanism step by step.

### Step-by-Step Solution:

1. **Understanding the \( S_N1 \) Mechanism**:
- The \( S_N1 \) (Substitution Nucleophilic Unimolecular) mechanism is a two-step process involving the formation of a carbocation intermediate.

2. **Step 1: Formation of Carbocation**:
- The first step in the \( S_N1 \) mechanism involves the departure of the leaving group, which leads to the formation of a carbocation. This step is unimolecular, meaning the rate of reaction depends only on the concentration of the substrate.

3. **Step 2: Nucleophilic Attack**:
- In the second step, a nucleophile attacks the carbocation formed in the first step. This step is bimolecular, as it involves both the carbocation and the nucleophile.

4. **Stability of Carbocation**:
- The stability of the carbocation is crucial in the \( S_N1 \) mechanism. The order of stability is tertiary > secondary > primary > methyl. More stable carbocations are favored in this mechanism.

5. **Solvent Effects**:
- The \( S_N1 \) mechanism typically occurs in polar protic solvents, which help stabilize the carbocation and the leaving group.

6. **Inversion of Configuration**:
- Unlike the \( S_N2 \) mechanism, which results in 100% inversion of configuration, the \( S_N1 \) mechanism does not guarantee inversion. The product may be a racemic mixture if the carbocation is planar.

7. **Elimination Reaction**:
- The \( S_N1 \) mechanism is primarily a substitution reaction, not an elimination reaction.

### Conclusion:
Based on the characteristics of the \( S_N1 \) mechanism, the correct statement is that it involves the formation of a carbocation.

### Final Answer:
The correct statement regarding the \( S_N1 \) mechanism is the **formation of a carbocation**.

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