Amolecule of unknown structure has a molecular formula of c9h8o2 . in the infrared spectrum there are absorptions at 1761, 1145, and 761 cm−1. in the c13 nmr spectrum, there are absorptions at δ 168.4, 152.0, 128.2, 128.0, 124.3, 122.8, 116.8, 29.1 and 23.6. in the h1 nmr spectrum, between δ 7.2 and 7.0, there is a complicated pattern that integrates to 4 protons. additionally, there are triplets at δ 3.0 and 2.7, each integrating to 2 protons. identify the structure of the unknown.