How can you identify the presence of an alcohol functional group using IR spectroscopy?

The presence of an alcohol functional group can be identified through infrared (IR) spectroscopy by the broad O-H stretching absorption peak that appears around 3200-3600 cm^-1. This peak is indicative of the hydroxyl (-OH) group found in alcohols. The broad nature of this peak is a characteristic feature due to hydrogen bonding between alcohol molecules, which causes variations in the O-H stretching frequency.

In IR spectroscopy, different functional groups absorb infrared light at specific wavelengths, and this O-H stretch is a strong and distinct feature that helps in confirming the presence of alcohols in a sample. The specific range of 3200-3600 cm^-1 is essential and helps differentiate alcohols from other functional groups that may produce peaks in different areas of the spectrum.

In contrast, other options do not accurately reflect the IR characteristics of alcohols. For instance, a sharp peak at 1700 cm^-1 typically corresponds to a carbonyl (C=O) stretch, not hydroxyl groups. The peak at 2500 cm^-1 is generally associated with carboxylic acids and would not be specific to alcohols, while the absence of any peaks in the carbon range would provide no information regarding functional groups. Therefore