To determine the chemical structure of the unknown compound, we need to analyze the proton NMR spectrum and consider the splitting patterns and chemical shifts.1. Triple peak at 1.2: This peak suggests a CH3 group adjacent to a CH2 group since it is split into a triplet . The chemical shift of 1.2 ppm indicates that it is likely an aliphatic CH3 group.2. Singlet peak at 2.0: This peak suggests a CH3 group that is not adjacent to any other protons, as it is not split. The chemical shift of 2.0 ppm indicates that it is likely an aliphatic CH3 group, possibly connected to an electronegative atom like oxygen.3. Doublet peak at 3.6: This peak suggests a CH2 group adjacent to a CH3 group since it is split into a doublet . The chemical shift of 3.6 ppm indicates that it is likely an aliphatic CH2 group connected to an electronegative atom like oxygen.4. Quartet peak at 7.5: This peak suggests a CH group adjacent to a CH2 group since it is split into a quartet . The chemical shift of 7.5 ppm indicates that it is likely an aromatic CH group.Based on this information, the unknown compound could be an ester with an aromatic ring. A possible structure is:O||C-O-CH2-CH3|C6H4-CH3This structure has an aromatic ring with a CH3 group singlet at 2.0 , an ester group connected to a CH2-CH3 group doublet at 3.6 and triplet at 1.2 , and an aromatic CH group quartet at 7.5 .