Concept:When a molecule contains both an aldehyde (\( -CHO \)) and a ketone (\( >C=O \)) group, the aldehyde has higher priority in IUPAC nomenclature and dictates the parent chain and suffix.
Solution:- The longest carbon chain containing both groups has 6 carbon atoms, so the parent name is hexanal.
- Numbering starts from the highly prioritized aldehyde carbon (C1).
- Counting down the chain: C1 (aldehyde), C2 (\( -CH_2- \)), C3 (ketone \( C=O \)).
- Because the ketone is treated as a substituent, it is named using the prefix oxo- (or keto-) at position 3.
- Therefore, the correct IUPAC name is 3-oxohexanal.
Why other options are incorrect:Options B and D end in '-ol', implying an alcohol is the principal functional group, which is false. Option C uses '-one' as a prefix, which is incorrect (it is a suffix for ketones when they have highest priority).
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