Order: n-Butanol > Acetone > Methoxyethane > Butane
Greater the polarity, higher the boiling point. n-Butanol has the highest boiling point among the given compounds due to H-bonding. Due to strong dipole-dipole interactions, carbonyl compounds have a higher boiling point than ethers of similar molecular mass which have weak dipole interactions.
Hydrocarbons have the lowest boiling points because they have weak dispersion forces only.