Consider the following four halomethanes: , , , and . Although their permanent dipole moments strict — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

Boiling points are dictated by the cumulative strength of all intermolecular forces. While dipole-dipole attractions decrease as the dipole moment drops from $CH_3Cl$ to $CCl_4$, the molecular mass and the total number of polarizable electrons significantly increase with the addition of each heavy chlorine atom. This massive increase in London dispersion forces completely overrides the loss of dipole-dipole interactions, resulting in a strict monotonic increase in boiling point: $CH_3Cl < CH_2Cl_2 < CHCl_3 < CCl_4$.