Question

What type of molecule has dipole-dipole interactions and what type has London dispersion forces?

Answer 1

Only polar molecules will show dipole-dipole interactions, and all will exhibit london-dispersion forces.

Explanation:

If you can figure out if the molecule in question is polar or not (be that by figuring out its molecular geometry or by looking at bond polarity) then you can tell if several of that molecule exhibit dipole-dipole intermolecular forces. All molecules will exhibit london-dispersion forces to a degree, though.