The reaction `C_2H_5OH+SOCl_2overset("Pyridine")rarrC_2H_5Cl+SO_2+HCl` is known as

Options

A. Kharasch effect
B. Darzen's procedure
C. Williamson's synthesis
D. Hunsdiecker reaction

Explanation

To solve the question regarding the reaction of ethanol with thionyl chloride (SOCl₂) in the presence of pyridine, we need to identify the name of this reaction. Here’s a step-by-step breakdown:

### Step 1: Identify the Reactants
The reactants in the given reaction are:
- Ethanol (C₂H₅OH)
- Thionyl chloride (SOCl₂)

### Step 2: Understand the Reaction Mechanism
In this reaction, thionyl chloride reacts with ethanol to convert the alcohol (ethanol) into an alkyl chloride (ethyl chloride, C₂H₅Cl). The reaction also produces sulfur dioxide (SO₂) and hydrochloric acid (HCl) as byproducts.

### Step 3: Role of Pyridine
Pyridine acts as a base in this reaction. It helps in the formation of the alkyl chloride by facilitating the departure of the leaving groups (SO₂ and HCl) and stabilizing the reaction intermediates.

### Step 4: Identify the Type of Reaction
The reaction involves the substitution of the hydroxyl group (-OH) in ethanol with a chlorine atom (Cl). This type of reaction is known for its inversion of configuration due to the backside attack of the nucleophile (Cl⁻) on the carbon atom.

### Step 5: Name the Reaction
This specific reaction is known as the **Darzen Procedure**. It is characterized by the conversion of alcohols to alkyl halides using thionyl chloride in the presence of a base like pyridine.

### Conclusion
Thus, the reaction `C₂H₅OH + SOCl₂ → C₂H₅Cl + SO₂ + HCl` is known as the **Darzen Procedure**.

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