Answer is: van der Waals forces and hydrogen bonds.
Intermolecular forces are the forces between molecules or particles.
There are several types of intermolecular forces: hydrogen bonding, ion-induced dipole forces, ion-dipole forces andvan der Waals forces.
Hydrogen bond is an electrostatic attraction between two polar groups that occurs when a hydrogen atom (H), covalently bound to a highly electronegative atom such as flourine (F), oxygen (O) and nitrogen (N) atoms.
Covalent bonds, ionic bonds and metallic bonds are intramolecular interactions, bonds between atoms in molecule.
