Identify the predominant intermolecular force in each of the following compounds.?

Question

CF4, CHF3, OF2, HF are placed in which categories, London dispersion, dipole-dipole, and hydrogen bonding?

Answer 1

CF4 = London (but I think that van der Waals forces are at work here too.)
CHF3 = OF2 = dipole-dipole
HF = hydrogen bonding

Answer 2

hydrogen bonding occurs in molecules with a hydrogen attached to an electronegative (attracts electrons) atoms such as Oxygen, or Fluorine. So in your question, HF would be the only hydrogen bonding molecule.

Dipole Dipole happens with polar molecules, and the intermolecular forces result from the charged end of the molecules being attracted with the oppositely charged ends of another, but same, molecule. that would be your OF2.

CF4 and CHF3 and london dispersion (if I remember correctly) because the molecule is balanced in charge and the tetrahedral structure give these molecules an even-charge effect (so no dipoles occur).

this should be in your book though so review!! :)