Question

Identify the product when ethylbenzene reacts with dilute nitric acid.

• A. o-Nitroethylbenzene
• B. p-Nitroethylbenzene
• C. Ethoxybenzene
• D. Benzic acid

Hint:

In electrophilic aromatic substitution reactions, electron-donating groups like alkyl groups direct substitution to the para position.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the product of the reaction between ethylbenzene and dilute nitric acid.
Step 2: Detailed Explanation:
While concentrated nitric acid in the presence of sulfuric acid usually nitrates the benzene ring, prolonged heating with dilute nitric acid acts as a strong oxidizing agent.
Strong oxidizing agents oxidize the alkyl side chain of a benzene ring all the way to a carboxyl group, provided the benzylic carbon has at least one hydrogen.
Ethylbenzene (\( \text{C}_6\text{H}_5\text{CH}_2\text{CH}_3 \)) has benzylic hydrogens, so the entire ethyl group is oxidized to form benzoic acid.
\[ \text{C}_6\text{H}_5\text{CH}_2\text{CH}_3 \xrightarrow{\text{dil. HNO}_3, \Delta} \text{C}_6\text{H}_5\text{COOH} \]
Step 3: Final Answer:
The product is benzoic acid.