Dipole-dipole interactions.
There are three classes of intermolecular interactions: London dispersion force, Dipole-dipole interaction, and hydrogen bonds.
Hydrogen bonds are observed only in molecules with hydrogen atoms bonded directly to atoms of fluorine, oxygen, or nitrogen that are of high electronegativity. Chloromethane [tex]\text{CH}_3\text{Cl}[/tex] contains no such bonds. Therefore, there would be no hydrogen bonds between molecules of [tex]\text{CH}_3\text{Cl}[/tex].
Dipole-dipole interactions are weaker than hydrogen bonds in most molecules. Dipole-dipole interactions exist only between polar molecules. Chloromethane contains polar carbon-chlorine bonds. Chloromethane molecules are asymmetric, such that polarity due to the presence carbon-chlorine bonds does not cancel out within the molecule. Chloromethane molecules are therefore polar, and would experience dipole-dipole interactions.
London distribution forces attribute to the movement of electrons within a molecule. Such interactions are transient and thus weaker than both hydrogen bonds and dipole-dipole interactions in small molecules such as [tex]\text{CH}_3\text{Cl}[/tex].
