The boiling point of ammonia (NH₃) is greater than that of phosphine (PH₃) due to the:

Dispersion forces

Dipole-dipole forces

Hydrogen bonding

Greater molar mass

Ammonia (NH₃) has a higher boiling point than phosphine (PH₃)

Ammonia exhibits hydrogen bonding, a stronger intermolecular force than the dipole-dipole forces in phosphine.