Which functional group transformation occurs in the product of the reaction catalyzed by ${\mathrm{Na}}^{+}$-NQR?

• A. A nitro group is reduced to an amine
• B. An alcohol is oxidized to a ketone
• C. A quinone is reduced to a hydroquinone
• D. An aldehyde is oxidized to a carboxylic acid

Answer: (C)

Verified step by step guidance

1. Identify the substrate involved in the reaction catalyzed by Na⁺-NQR. Na⁺-NQR is known to catalyze redox reactions involving quinones.
2. Recall the structure and properties of quinones and hydroquinones. Quinones have a conjugated diketone structure, while hydroquinones are their reduced form with two hydroxyl groups replacing the ketones.
3. Understand that the transformation from quinone to hydroquinone involves a reduction process, where the carbonyl groups (=O) in quinones are converted to hydroxyl groups (-OH).
4. Compare the other options: reduction of a nitro group to an amine, oxidation of an alcohol to a ketone, and oxidation of an aldehyde to a carboxylic acid. These are different types of transformations not catalyzed by Na⁺-NQR.
5. Conclude that the functional group transformation catalyzed by Na⁺-NQR is the reduction of a quinone to a hydroquinone, which involves the gain of electrons and protons to convert carbonyl groups into hydroxyl groups.