What is the main difference between a primary alcohol and a secondary alcohol?

The distinction between primary and secondary alcohols is significantly based on the position of the hydroxyl (-OH) group in relation to the carbon atoms in the molecule. In primary alcohols, the -OH group is attached to a carbon atom that is at the end of the carbon chain, referred to as a terminal carbon. This carbon, in turn, is only connected to one other carbon atom (or none, in the case of methanol). In contrast, secondary alcohols have the -OH group attached to a carbon that is bonded to two other carbon atoms, placing it within the carbon chain rather than at the end.

Understanding this structural arrangement is crucial in organic chemistry as it affects the properties and reactivity of the compounds. For example, primary alcohols are generally more oxidizable than secondary alcohols, which is relevant in various chemical reactions and syntheses.

The incorrect options confuse the definitions or misplace the functional groups. For instance, secondary alcohols do not have the -OH group on terminal carbons and do not necessarily possess multiple -OH groups. Understanding this basic structure helps in correctly identifying and naming alcohols in organic chemistry.