Unknown Y has a molecular formula for C 3H4 O2 . It contains one functional group that absorbs infrared radiation in the 3200-3550 cm region (when studied aaas a pure liquid; i.e., "neat"), and it has no absorption in the 1620-1780 cm region. No carbon atom in the structure of Y has more than one oxygen atom bonded to it, and Y can exist in two (and only two) stereoisomers forms. What are the structures of these forms of Y?