In which of the following, functional group isomerism is not possible?
(i) Alcohols
(ii) Aldehydes
(iii) Alkyl halides
(iv) Cyanides
The answer is the option (iii) Alkyl halides
Explanation: Isomerism is a phenomenon in which two compounds have the exact same molecular formula, but the different structural formula and such compounds are called isomers, and Functional isomers have same molecular formula but a different functional group. Alcohols are functional isomers of ethers. Aldehydes are functional isomers of ketones. Cyanides are functional isomers of isocyanides. Only alkyl halides do not show functional isomerism.