Identify correct statements from the following : A. Propanal and propanone are functional isomers. B. Ethoxyethane and methoxypropane are metamers. C. But-2-ene shows optical isomerism. D. But-1-ene and but-2-ene are functional isomers. E. Pentane and 2, 2-dimethyl propane are chain isomers. Choose the correct answer from the options given below :

Step-by-step solution

A. Propanal ( CH₃CH₂CHO ) and propanone ( CH₃COCH₃ ): Same formula C₃H₆O , different functional groups (aldehyde vs ketone) → Functional isomers. True B. Ethoxyethane ( C₂H₅OC₂H₅ ) and methoxypropane ( CH₃OC₃H₇ ): Same ether group, different alkyl groups → Metamers. True C. But-2-ene ( CH₃CH=CHCH₃ ): No chiral carbon, shows geometrical isomerism (cis-trans), not optical. False D. But-1-ene and but-2-ene: Both are alkenes, differ in position of double bond → Position isomers, not functional isomers. False E. Pentane