Final answer:
Ketone IR spectra are characterized by a strong carbonyl absorption peak around 1715 cm¹, corresponding to the C=O stretching vibration, with additional unique peaks in the fingerprint region (400 - 1400 cm¹), which aid in molecular identification.
Step-by-step explanation:
The IR spectrum for ketone peaks is particularly distinctive due to the presence of the carbonyl functional group. Typically, ketones exhibit a strong absorption peak in the infrared spectrum at a wavenumber around 1715 cm¹, corresponding to the C=O stretching vibration. This peak is indicative of the carbonyl group and can vary slightly in position based on the ketone's specific structure and other interacting functional groups. The carbonyl bond absorbs at a frequency of about 5.15 x 10¹³ Hz, which corresponds to a wavelength of approximately 5.86 μm (micrometers), and this interaction requires an energy change (ΔE) of about 4.91 kcal/mol. Additionally, the fingerprint region, ranging from 400 - 1400 cm¹, includes numerous peaks that are unique to each molecule, making it a valuable tool for molecular identification.