Ethylene glycol when heated in the presence of anhydrous `ZnCl_(2)` yields

Options

A. vinyl alcohol
B. ethyl alcohol
C. acetadehye
D. acetic acid

Answer

To solve the question regarding the product formed when ethylene glycol is heated in the presence of anhydrous ZnCl₂, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactant is ethylene glycol, which has the chemical formula \( \text{C}_2\text{H}_6\text{O}_2 \) or \( \text{CH}_2\text{OH-CH}_2\text{OH} \).

2. **Understand the Role of Anhydrous ZnCl₂**:
- Anhydrous zinc chloride (\( \text{ZnCl}_2 \)) acts as a dehydrating agent. This means it will facilitate the removal of water (H₂O) from the ethylene glycol.

3. **Dehydration Reaction**:
- When ethylene glycol is heated with anhydrous ZnCl₂, a dehydration reaction occurs. The hydroxyl (–OH) group from one carbon and a hydrogen (–H) from the adjacent carbon are removed, resulting in the formation of a double bond between the two carbon atoms.
- The reaction can be represented as:
\[ \text{CH}_2\text{OH-CH}_2\text{OH} \xrightarrow{\text{ZnCl}_2} \text{CH}_2=CH\text{OH} + \text{H}_2\text{O} \]
- This results in the formation of vinyl alcohol (enol form).

4. **Tautomerization**:
- Vinyl alcohol (enol) is not very stable and undergoes tautomerization to form acetaldehyde (keto form). The tautomerization can be represented as:
\[ \text{CH}_2=CH\text{OH} \rightleftharpoons \text{CH}_3\text{CHO} \]
- Thus, the final product is acetaldehyde.

5. **Conclusion**:
- The product formed when ethylene glycol is heated in the presence of anhydrous ZnCl₂ is acetaldehyde.

### Final Answer:
The correct answer is **acetaldehyde**.

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