Which pair of compounds are functional group isomers?

  • A. Propan-1-ol and propan-2-ol
  • B. Butane and 2-methylpropane
  • C. Propanal and propanone
  • D. Ethane and propane

Explanation

Propanal is an aldehyde and propanone a ketone, yet both have the molecular formula C3H6O, so they differ in functional group. The two propanols differ only in the position of the same hydroxyl group, making them position isomers, and butane with 2-methylpropane are chain isomers. Ethane and propane are homologues, not isomers, since their formulae differ.

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