What is the typical absorption peak range for carbonyl functional groups in infrared spectroscopy?

The typical absorption peak range for carbonyl functional groups in infrared spectroscopy is around 1700 cm-1. This is where the C=O stretching vibration occurs, which is a prominent feature in the IR spectrum of compounds containing carbonyl groups like ketones, aldehydes, carboxylic acids, and esters.

The C=O bond is strong and thus absorbs infrared radiation at this specific wavenumber. The exact position of the absorption peak can vary slightly depending on the specific environment of the carbonyl group, such as whether it is part of a conjugated system or is involved in hydrogen bonding. However, 1700 cm-1 is generally accepted as the characteristic absorption region for carbonyl groups, making it a key marker in identifying such functional groups in organic compounds.

Other absorption peaks mentioned in the choices correspond to different functional groups or molecular vibrations. For instance, absorption peaks around 3000 cm-1 are typically associated with O-H and N-H stretching, while peaks near 2500 cm-1 may indicate the presence of C-H stretching or other less common functional groups. Peaks around 1500 cm-1 are generally related to C-C stretching or bending vibrations, which are distinct from the characteristic C=