Based on the given information from the infrared IR spectrum, we can make some educated guesses about the chemical structure of the unknown compound.1. A peak at 3500 cm^-1 is indicative of an O-H or N-H bond. This suggests that the compound may contain an alcohol R-OH , amine R-NH2 , or amide R-CONH2 functional group.2. The absence of peaks between 1600-1800 cm^-1 suggests that the compound does not contain a carbonyl group C=O , as carbonyl stretches typically appear in this region. This rules out the possibility of the compound being an amide.Considering the information provided, the unknown compound likely contains either an alcohol R-OH or amine R-NH2 functional group. However, without more information from the IR spectrum or other analytical techniques, it is not possible to determine the exact chemical structure of the compound.