Which of the following statements correctly describes the Lewis dot structure of neutral butyric acid (C4H8O2)?

• A. It contains a carboxyl group (COOH) with both oxygens double-bonded to the same carbon atom.
• B. It contains a carboxyl group (COOH) with both oxygens single-bonded to the same carbon atom, and no hydrogen attached to the oxygens.
• C. It contains a carboxyl group (COOH) with a double bond between carbon and one oxygen, and a single bond between carbon and the other oxygen, which is also bonded to a hydrogen atom.
• D. It contains a carboxyl group (COOH) with a triple bond between carbon and one oxygen.

Answer: (C)

Verified step by step guidance

1. Recall the general structure of a carboxyl group (COOH) found in carboxylic acids like butyric acid. The carboxyl group consists of a carbon atom double-bonded to one oxygen atom and single-bonded to another oxygen atom, which is also bonded to a hydrogen atom.
2. Understand that in the Lewis dot structure, the carbon in the carboxyl group forms a double bond with one oxygen to satisfy the octet rule and a single bond with the other oxygen, which carries a hydrogen atom, making it a hydroxyl group (-OH).
3. Recognize that both oxygens cannot be double-bonded to the same carbon atom because that would violate typical bonding patterns and the octet rule for oxygen atoms in carboxylic acids.
4. Note that a triple bond between carbon and oxygen in a carboxyl group is not chemically correct for carboxylic acids, as it would not allow the formation of the hydroxyl group necessary for the acidic properties.
5. Conclude that the correct Lewis structure for the carboxyl group in butyric acid has one carbon-oxygen double bond and one carbon-oxygen single bond with the oxygen in the single bond also bonded to a hydrogen atom.