Concept:Ketones contain a polyvalent carbonyl functional group (\( \text{-C=O} \)) flanked by two alkyl chains. Isomerism caused by varying these alkyl chain lengths is known as metamerism.
Solution:- 2-Hexanone: \( \text{CH}_3\text{-CO-C}_4\text{H}_9 \). The alkyl groups attached to the carbonyl are methyl and butyl.
- 3-Hexanone: \( \text{C}_2\text{H}_5\text{-CO-C}_3\text{H}_7 \). The alkyl groups attached to the carbonyl are ethyl and propyl.
- Because the functional group is identical but the distribution of carbon atoms on either side of it differs, they are best classified as metamers.
- Note: While sometimes broadly classified as position isomers, metamerism is the more specific and preferred term for polyvalent functional groups like ketones and ethers.
Why other options are incorrect:The main chain length (6 carbons) hasn't branched, ruling out chain isomerism. The functional group remains a ketone, ruling out functional isomerism.
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