Answer:
Phosgene has a higher boiling point.
Sulfur trioxide has a higher boiling point.
Explanation:
Phosgene has a higher boiling point than formaldehyde because it has a larger molar mass.
Sulfur trioxide has a higher boiling point due to its molecular shape (trigonal planar) and stronger dipole-dipole interactions. Furthermore, it has a larger molar mass.