Question

What is the identity of an unknown compound that shows a strong absorption at 1700 cm⁻¹ in its IR spectrum and displays a singlet at 2.2 ppm in its ¹H NMR spectrum?

Answer 1

The strong absorption at 1700 cm in the IR spectrum suggests the presence of a carbonyl group  C=O  in the compound. The singlet at 2.2 ppm in the H NMR spectrum is indicative of a methyl group  CH3  adjacent to the carbonyl group. Based on this information, the unknown compound is likely to be an aldehyde or a ketone with a methyl group adjacent to the carbonyl group.A possible candidate for the unknown compound is acetone  CH3-CO-CH3 , which has a carbonyl group and two methyl groups adjacent to it. The IR absorption and H NMR chemical shift values are consistent with the properties of acetone.