What is the difference between hydrogen bonds, van der Waals forces, and polarity?

Answer 1

Polarity is the essential driving force of hydrogen bonds and van der waals forces. Hydrogen bonding is the intermolecular attractive force between molecules that possess either a H-O, H-N, or H-F in their structure. Hydrogen bonding (a.k.a. hydrogen intermolecular attractive forces) are the strongest intermolecular force. Van der Waals forces are the intermolecular forces that are present between polar molecules. For example, HCl is a polar molecule with a slight negative charge on the Cl end and a slight positive charge on the H end. HCl molecules would be attracted to each other because of this permanent dipole (two poles), thus, the intermolecular attractive forces are van der waals forces, a.k.a. permanent dipole-permanent dipole forces.