Using the intermolecular forces of attraction concept, explain why propionic acid (bp = 141 °C) has a higher boiling point than propaneperoxoic acid (bp = 120°C; explodes) even though the former has a lower molecular weight than the latter.

• A. Propionic acid molecules possess stronger Van der Waals forces.
• B. Propionic acid molecules form stable H-bonded dimers, doubling the molecular weight and increasing the energy required to disrupt the interactions and allow the molecules to escape from the liquid phase.
• C. Propionic acid molecules form stable H-bonded trimers, tripling the molecular weight and increasing the energy required to disrupt the interactions and allow the molecules to escape from the liquid phase.
• D. Propionic acid molecules possess weaker Van der Waals forces.

Answer: (B)