Question

Which compound matches the IR spectrum best?

Answer 1

The IR spectrum shows the peaks at ~3000 cm and1710 cm (strong peaks). It doesn't show the peaks for the benzene ring andits derivatives, which are less than 1000 cm-1 So, benzene derivatives can be eliminated Thus, structures B, E andF can be eliminated Now, check with the structures A, C and D. It doesn't show the peak at 690-515 cm- (C-Br). So, structure A can be eliminated The aliphatic aldehyde shows the C-O peak at 1650-1670 cm-1. Aliphatic cyclohexanone/cyclopentanone shows the peak at 1725-1705 cm From the above information, the structure D would be the required compound. Therefore, the compound whi ch matches with the IR spectra is structure D