Explain why thionyl chloride method is preferred for preparing alkyl chlorides from alcohols.

Explanation

To explain why the thionyl chloride method is preferred for preparing alkyl chlorides from alcohols, we can follow these steps:

### Step 1: Reaction Overview
When an alcohol (R-OH) reacts with thionyl chloride (SOCl2), it forms an alkyl chloride (R-Cl) along with byproducts, which are sulfur dioxide (SO2) and hydrochloric acid (HCl).

### Step 2: Reaction Mechanism
The reaction can be summarized as follows:
\[ R-OH + SOCl2 \rightarrow R-Cl + SO2 + HCl \]
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