1. The following are the proton and carbon-13 spectra of 4 compounds with the molecular formula , C4H8O2. Identify their structures and name them.

A.

B.

C.

D.

2. A compound is 69.6% C, 7.24% H, and 23.2% O. When 0.3 grams of the compound is dissolved in 10 g of t-butyl alchohol (K_f=8.2 ^oC/m) the freezing point of the solution is 23.1 ^oC compared to 24.9 ^oC for the pure solvent. The compound has the following C-13 and H NMR. a) What is the empirical formula of the compound? b) What is the molecular formula of the compound? What is the structure and name of the compound?