Question

minimum number of carbons required to show metamerism​

Answer 1

Ketone having the functional group of /\C=O needs minimum 5 carbons to show positional Isomerism.Because minimum 3 carbons are needed to form a ketone.[CH3-CO-CH3].IT has no Isomer.If we consider the butanone[CH3-CO-CH2-CH3] ,It also doesn’t show any positional Isomerism.But ketone with 5 carbons has isomers like CH3CH2-CO-CH2CH3 and C3H7-CO-CH3,….etc

Answer 2

$\huge{\underline{\underline{\boxed{\sf{\red{5}}}}}}$