Final answer:
The compound with the highest boiling point among C3H8, CH3COOH, CH4, and C2H6 is CH3COOH (acetic acid) because it has hydrogen bonds, which are stronger than the London dispersion forces in the other nonpolar hydrocarbons.
Step-by-step explanation:
Out of the compounds C3H8, CH3COOH, CH4, and C2H6, the one with the highest boiling point is CH3COOH (acetic acid).
This is because CH3COOH can form hydrogen bonds due to the presence of the hydroxyl group (-OH), which is characteristic of carboxylic acids. Hydrogen bonding is a strong intermolecular force that requires more energy to break compared to the London dispersion forces present in nonpolar molecules like C3H8 (propane), CH4 (methane), and C2H6 (ethane).
The boiling points of hydrocarbons increase with molecular size due to increased London dispersion forces, hence C2H6 has a lower boiling point than C3H8. However, due to hydrogen bonding, CH3COOH has a significantly higher boiling point than the other compounds listed, which only exhibit London dispersion forces.