What is the general structure of a ketone?

The structure of a ketone is represented as R-C=O-R, where "R" and "R'" are hydrocarbon groups (which can be the same or different), and "C=O" denotes the carbonyl group. In a ketone, the carbonyl carbon is bonded to two other carbon atoms, distinguishing it from other functional groups like aldehydes, in which the carbonyl carbon is bonded to at least one hydrogen atom.

The carbonyl (C=O) group is key to identifying ketones, as it plays a crucial role in their chemical properties and reactivity. This specific structure allows ketones to engage in various reactions typical for compounds that have a carbonyl group, such as nucleophilic addition.

Other options contain functional groups that don't accurately represent ketones. For instance, the presence of an –OH group in one option suggests a carboxylic acid or an alcohol rather than a ketone. The other structures include nitrogen functionalities or incorrect bonding patterns that do not align with the definition or characteristics of ketones. Thus, the general structure of a ketone clearly is R-C=O-R.