Answer
🔬 Identifying Electron-Accepting Sites in the Reaction
In the reaction shown in the image below, we are tasked with identifying the electron-accepting sites. These are sites that act as Lewis acids—they accept a pair of electrons during the reaction.
🔍 Structural Analysis
The molecule on the left is benzoic acid (C₆H₅COOH), and the species on the right is the hydronium ion (H₃O⁺).
In this context, the reaction likely involves protonation by H₃O⁺. Since H₃O⁺ donates a proton (H⁺), it acts as a Bronsted acid, and the molecule accepting the proton acts as a Lewis base. However, we are interested in which part of the benzoic acid acts as an electron acceptor.
🧠 Electron-Accepting (Lewis Acid) Sites
- The carbon atom of the carbonyl group (C=O) is electrophilic due to the polarity of the double bond. This makes it a common site for electron acceptance, especially in nucleophilic reactions.
- In acidic conditions, the carbonyl oxygen can also get protonated, making the carbon even more electrophilic. In that case, the oxygen accepts a proton, behaving temporarily as a Lewis base, while the carbon accepts electrons from the attacking group.
✅ Conclusion: The primary site that accepts electrons in this reaction is the carbon of the carbonyl group in the benzoic acid molecule.
Understanding electron flow is essential in predicting reactivity and mechanisms in organic chemistry. Identifying these electron-deficient (electrophilic) sites helps in mastering reaction prediction.