Which of the following is a characteristic of a primary alcohol?

A primary alcohol is defined by the structure where the hydroxyl group (-OH) is attached to a carbon atom that is bonded to only one other carbon atom. This unique configuration is crucial as it affects the chemical properties and reactivity of primary alcohols compared to secondary and tertiary alcohols. When identifying a primary alcohol, one recognizes that the relevant carbon is effectively at the end of a carbon chain, making it less hindered and more accessible for certain reactions.

In this context, the other options do not correctly describe the characteristics of primary alcohols. For example, having a carbon bonded to three other carbons would actually characterize a tertiary alcohol, while the oxidation of primary alcohols typically results in the formation of aldehydes, not ketones. Furthermore, primary alcohols tend to be more reactive in certain oxidation reactions than secondary alcohols due to differences in steric hindrance and available hydrogen atoms for oxidation. This structural understanding is key to recognizing the nature and behavior of alcohols in organic chemistry.