Which ion is formed from the deprotonation of butanoic acid?

The correct answer is the butanoate ion, which is formed when butanoic acid, a carboxylic acid, loses a proton (H⁺).

In organic chemistry, deprotonation refers to the removal of a hydrogen ion from a molecule, resulting in the formation of its conjugate base. For butanoic acid, which has the molecular formula CH₃CH₂CH₂COOH, the deprotonation occurs at the carboxylic acid functional group (-COOH). When butanoic acid loses a proton, it transforms into butanoate, which carries a negative charge due to the loss of the positively charged hydrogen ion.

This ion is conventionally named by replacing the '-ic acid' suffix of the parent acid with '-ate,' which is standard nomenclature for carboxylic acids and their conjugate bases. Hence, the ion formed is designated as butanoate (or butanoate ion), indicating that it is derived from butanoic acid.

The other choices do not accurately reflect the ion formed from deprotonating butanoic acid. Butanoic ion does not exist as a recognized term in organic nomenclature, while butane is a hydrocarbon and does