Question

Give proper reasoning for the following:

•n-Butyric acid is a slightly stronger acid than isobutyric acid?
A) n-Butyric acid has a higher molecular weight, leading to stronger intermolecular forces and higher acidity compared to isobutyric acid.
B) n-Butyric acid has a longer carbon chain, allowing for a more stable conjugate base, making it slightly stronger than isobutyric acid.
C) n-Butyric acid contains a linear carbon structure, facilitating resonance stabilization of the conjugate base, resulting in higher acidity than isobutyric acid.
D) n-Butyric acid has a larger number of hydrogen atoms, leading to stronger hydrogen bonding and higher acidity compared to isobutyric acid.

Answer 1

n-Butyric acid is a slightly stronger acid than isobutyric acid because its longer carbon chain leads to a more stable conjugate base due to better electron distribution, not because of molecular weight, resonance stabilization, or the number of hydrogen atoms.

Step-by-step explanation:

The correct reasoning for why n-Butyric acid is a slightly stronger acid than isobutyric acid is related to the structure of its conjugate base and the effect of the alkyl chain on the acid's strength.

Option B) n-Butyric acid has a longer carbon chain, allowing for a more stable conjugate base, making it slightly stronger than isobutyric acid makes the most sense. This is because a longer carbon chain allows for greater electron distribution throughout the molecule, leading to less electron density on the carboxylate group, thus a more stable conjugate base. A more stable conjugate base corresponds to a stronger acid.

Options A), C), and D) are incorrect because molecular weight does not directly relate to acidity, resonance stabilization does not apply here (since neither molecule has a resonance-stabilized conjugate base), and the number of hydrogen atoms does not determine the strength of a carboxylic acid.