What is the general structure of aldehydes?

Aldehydes are characterized by the presence of a carbonyl group (C=O) that is bonded to a hydrogen atom and a carbon-containing group, represented as R in the general structure. The formula RCHO effectively shows that one side of the carbonyl carbon (C) is connected to a hydrogen atom (H), while the other side is attached to an alkyl group (R). This structural arrangement is what distinguishes aldehydes from other functional groups.

In contrast, the other options illustrate different types of compounds. The first option, with the formula RCOOH, represents carboxylic acids, which contain both a carbonyl and a hydroxyl group. The third option, RCOOR', signifies esters, where the carbonyl is bonded to an alkoxy group instead of a hydrogen. The fourth option, R-NH2, indicates amines, which are characterized by the presence of nitrogen bound to hydrogen atoms and carbon groups, lacking a carbonyl group altogether.

Thus, the identification of aldehydes as having the RCHO structure is fundamental and highlights their unique functional properties within organic chemistry.