`PhCH_(2)CH_(3) overset((i)CrO_(2)Cl_(2)//"CCl"_(4))underset((ii)H_(3)O^(+))rarrPhCH_(2)CHO`
The above reaction is an example of which name reaction?

Options

A. Rossenmund reduction
B. Birch reduction
C. Mendius reduction
D. Etard reduction

Answer

To determine the name of the reaction given in the question, we need to analyze the reactants and products involved in the transformation.

### Step-by-Step Solution:

1. **Identify the Reactants and Products:**
- The starting compound is PhCH₂CH₃ (ethylbenzene).
- The product is PhCH₂CHO (benzaldehyde).

2. **Understanding the Reaction Conditions:**
- The reaction is carried out using CrO₂Cl₂ in CCl₄ followed by treatment with H₃O⁺ (hydronium ion).
- CrO₂Cl₂ is a strong oxidizing agent.

3. **Recognizing the Type of Reaction:**
- The reaction involves the oxidation of ethylbenzene (PhCH₂CH₃) to form an aldehyde (PhCH₂CHO).
- This transformation is characteristic of the Etard reaction, which specifically oxidizes alkyl groups on aromatic rings to form aldehydes.

4. **Confirming the Reaction Type:**
- The Etard reaction is named after the chemist who discovered it, and it is known for converting alkyl aromatic compounds into corresponding aromatic aldehydes using chromium-based oxidants.

5. **Conclusion:**
- Given that the reaction involves the oxidation of ethylbenzene to benzaldehyde using CrO₂Cl₂, we can conclude that the reaction is an example of the **Etard reaction**.

### Final Answer:
The reaction is an example of the **Etard reaction**.

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