Question

Explain why methyl propionate(bp=80 degrees celcieus)and butyric acid (bp=163 degrees celcieus) have the same molecular weights but different boiling points.

Answer 1

Methyl propionate and butyric acid have the same molecular weight but different boiling points.

Explanation: The butyric acid contains the carboxylic acid functional group (-C(=O)-OH), hence it can exhibit intermolecular hydrogen bonding, whereas the methyl propionate has an ester functional group (-C(=O)-OR), so it's incapable to exhibit hydrogen bonding. Hence, due to the presence of strong intermolecular hydrogen bonding in the butyric acid, it has higher boiling point than that of methyl propionate.