Question

7. How could you distinguish between the following pair of compounds from their IR
spectra? HOCH2CH2CHO (3-hydroxypropanal) andCH3CH2COOH (propanoic acid)​

Answer 1

Explanation:

The main differences between these molecules' IR spectra are in the OH stretches and in the C=O stretches.

While the alcohol OH stretch is broader, the carboxylic OH stretch is less broad. While the aldehyde C=O stretch is sharp and "well-defined", the carboxylic C=O stretch is broader and more "smeared".