A solution of (+)2-chloro-2-phenylethane in toluene racemises slowly in the presence of small amount of `SbCl_(5)` due to the formation of-

Options

A. Carbanion
B. Carbene
C. Free-radical
D. Carbocation

Answer

To solve the problem, we need to analyze the racemization of (+)2-chloro-2-phenylethane in toluene when a small amount of SbCl5 is present. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Concept of Racemization
Racemization refers to the process where an optically active compound converts into a racemic mixture, which contains equal amounts of both enantiomers. This typically occurs through a reaction mechanism that allows for the formation of a planar intermediate, which can be attacked from either side.

**Hint:** Remember that racemization involves the formation of a racemic mixture, which contains both enantiomers.

### Step 2: Identify the Reaction Mechanism
In this case, the racemization of 2-chloro-2-phenylethane is likely occurring through an SN1 mechanism. The SN1 mechanism involves the formation of a carbocation intermediate, which is crucial for racemization to happen.

**Hint:** Think about the types of reactions that lead to racemization and the role of carbocations in these reactions.

### Step 3: Formation of the Carbocation
When 2-chloro-2-phenylethane reacts in the presence of SbCl5, the chlorine atom acts as a leaving group. This results in the formation of a carbocation. The stability of this carbocation is enhanced by resonance with the adjacent phenyl group.

**Hint:** Consider how the stability of the carbocation affects the reaction pathway and the likelihood of racemization.

### Step 4: Attack of the Nucleophile
Once the carbocation is formed, it can be attacked by a nucleophile (like OH-) from either side of the planar carbocation. If the nucleophile attacks from the same side as the leaving group, it retains the original configuration. If it attacks from the opposite side, it results in inversion of configuration.

**Hint:** Visualize the carbocation structure and how the nucleophile can approach it from different angles.

### Step 5: Formation of the Racemic Mixture
Since the nucleophile can attack from both sides, the final products will be a mixture of both configurations (retention and inversion), leading to a racemic mixture.

**Hint:** Remember that the formation of both configurations is what defines a racemic mixture.

### Conclusion
The racemization of (+)2-chloro-2-phenylethane in toluene in the presence of SbCl5 occurs due to the formation of a carbocation intermediate, which allows for the attack of the nucleophile from either side, resulting in a racemic mixture.

**Final Answer:** The correct answer is the formation of a **carbocation**.