There are three intermolecular forces of ethanol. They are London dispersion, dipole-dipole and the hydrogen bond. All three of these forces are different due to of the types of bonds they form and their various bond strengths.
The first force, London dispersion, is also the weakest. In London dispersion, the intermolecular attraction occurs between every molecule. This is caused by the exchange of electrons between each molecule when they are polarized temporarily. This temporary polarization occurs when the electron density is higher on one side of the molecule than the other.
Dipole-dipole attraction occurs because ethanol is a polar molecule with both one positively charged and one negatively charged end. Because the positive and negative charges are attracted to each other, the opposite poles of each molecule form bonds. This attraction is stronger than London dispersion but weaker than the third type of attraction, hydrogen bonds.
The final force is the hydrogen bond. Hydrogen bonds occur when the proton bonds with the pair of oxygen electrons in the molecule. The molecule that provides this bond is known as the donor, while the molecule that has the electrons the hydrogen is attracted to is known as the acceptor. Ethanol contains the O-H bond, allowing it to create a hydrogen bond.