How can you identify a primary alcohol?

A primary alcohol is characterized by the structure of its carbon atom to which the hydroxyl group (-OH) is attached. Specifically, in a primary alcohol, the hydroxyl group is attached to a carbon atom that is bonded to only one other carbon atom. This means that this carbon is at the end of a carbon chain, resulting in the general formula R-CH2OH, where R represents the rest of the hydrocarbon chain.

Understanding this definition helps differentiate primary alcohols from secondary and tertiary alcohols. In secondary alcohols, the carbon with the -OH group is connected to two other carbons, and in tertiary alcohols, it is bonded to three other carbons. Therefore, the structural characteristics outlined in the correct choice help define primary alcohols distinctly from other types, solidifying the identification based on the connectivity of the carbon atom in question.

This clear distinction is crucial in organic chemistry, especially when determining the properties, reactivity, and classification of different alcohols.