How can you differentiate between aldehydes, ketones, and carboxylic acids using IR spectroscopy?
Understand the Problem
The question is asking how to differentiate between aldehydes, ketones, and carboxylic acids using IR spectroscopy. It presents multiple choice answers related to the spectral characteristics of these compounds.
Answer
D.
The final answer is D. All compounds will show a sharp peak at 1700 cm-1 but only one will show medium strength bands around 2800 and 2700 cm-1, and one will show a broad band from 3100 to 2800 cm-1.
Answer for screen readers
The final answer is D. All compounds will show a sharp peak at 1700 cm-1 but only one will show medium strength bands around 2800 and 2700 cm-1, and one will show a broad band from 3100 to 2800 cm-1.
More Information
Aldehydes and ketones show a strong peak around 1700 cm^-1. Aldehydes have additional peaks near 2800-2700 cm^-1, while carboxylic acids show a broad peak 3100-2800 cm^-1 due to O-H stretching.
Tips
Not accounting for the O-H broad band for carboxylic acids can lead to errors.
Sources
- IR Spectroscopy Characteristic Absorption Bands - chem.libretexts.org
