Higher than 59 °C because dipole-dipole interactions in iodine monochloride are stronger than dispersion forces in bromine.
Explanation:
Intermolecular forces are broadly classified into four types:
1) Ionic
2) Hydrogen bonding
3) Dipole-dipole
4) London dispersion
The strongest is the ionic interaction while the weakest are the dispersion forces. Bromine () is a non-polar molecule due to the absence of a permanent dipole. The only force of attraction in non-polar molecules are the weak dispersion forces.
In contrast iodine monochloride () is a polar molecule which are held together dipole-dipole forces that are stronger than the London dispersion forces.
Hence, the boiling point of () would be higher than that of ()