1. This question is about the determination of the structure of an unknown compound, B.

Compound B is a trans stereoisomer that is a useful intermediate in organic synthesis. 

Analysis of compound B shows it to contain 68.6 % carbon, 8.6 % hydrogen and 22.8 % oxygen.

The infrared spectrum of the compound B is shown in Figure 1.

Figure 1

In the mass spectrum, shown in Figure 2, the peak with the greatest relative intensity is caused by the loss of a functional group from the molecular ion of the compound B.

Figure 2

Determine the structure of compound B. Explain your reasoning and show your working.