Dispersion forces are those forces that occur between two non polar molecules.They form the weakest bonds.Here electrons of one molecule is attracted to the nucleus of the other molecule. Example are;
Interaction of two methyl (-CH₃) group
Interaction between nitrogen gas , N₂ molecules
Interaction between oxygen gas ,O₂ molecules
Dipole-Dipole interaction happens when two polar molecules interact.Positive charges in one molecule is attracted to negative charge of another molecule.Examples
Chloroform (CHCl₃)
Ammonia (NH₃)
Hydrogen bonding are created when an hydrogen atom bonded to an electronegative atom is attracted to a another electronegative atom.Example is the hydrogen bond between oxygen atom and hydrogen is water (H₂O).