JAMB Chemistry 2018 Paper

Concept:Alkanones are the IUPAC class name for ketones, so their general formula is based on the carbonyl group bonded to two carbon-containing groups.Explanation:A ketone has a carbonyl group $\mathrm{C=O}$ attached to two alkyl or aryl groups.Therefore, its condensed general formula is written as $\mathrm{R}_2\mathrm{CO}$.Examples include propanone: $\mathrm{CH}_3\mathrm{COCH}_3$.The options represent:• A: $\mathrm{RCHO}$ is an alkanal (aldehyde).• B: $\mathrm{R}_2\mathrm{CO}$ is an alkanone (ketone).• C: $\mathrm{RCOOH}$ is an alkanoic acid.• D: $\mathrm{RCOOR}$ is an alkanoate (ester).Thus the correct general formula must match the ketone structure.Answer:B. $\mathrm{R}_2\mathrm{CO}$