small peak at 3000large peak at 1685F: it contains two benzene rings that is connected by a bunch of carbons and ketone-Explanation: The spectrum shows a stretching absorption consistent with a ketone functional group: carbonyl C=O stretching at ~1685 cm-1. (An aldehyde, by contrast, would also show a ~2700 cm-1 absorption for the carbonyl C-H stretch.) The C=O stretching frequency is consistent with an aromatic ketone, such as in compound F (1,4-diphenyl-1,4-butanedione). In contrast, an aliphatic ketone absorbs at higher energy (~1710 cm-1). The spectrum also shows the typical ~1600 & ~1500 cm-1 absorptions of a phenyl group.
