what are the order intermolecular forces according to strength??

dispersion forces < dipole-dipole interactions < hydrogen bonds

http://www.ausetute.com.au/intermof.html

The order of intermolecular forces according to strength, from weakest to strongest, is as follows:

1. Van der Waals forces: These are the weakest intermolecular forces and can be divided into two types:

a. London dispersion forces: These forces arise from temporary fluctuations in electron distribution around atoms or molecules. They occur in all molecules, regardless of polarity. The strength of London dispersion forces increases with the size/molar mass of the molecules.

b. Dipole-dipole interactions: These occur between polar molecules, where one end of the molecule has a partial positive charge and the other end has a partial negative charge. The positive region of one molecule is attracted to the negative region of another. The strength of dipole-dipole interactions depends on the magnitude of the dipole moment and the distance between the molecules.

2. Hydrogen bonding: This is a special type of dipole-dipole interaction that occurs between a hydrogen atom bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and another highly electronegative atom in a different molecule. Hydrogen bonds are stronger than regular dipole-dipole interactions due to the large difference in electronegativity and the small size of the hydrogen atom.

3. Ion-dipole interactions: These occur between an ion (charged particle) and a polar molecule. The positive or negative charge of the ion is attracted to the opposite partial charge on the polar molecule. Ion-dipole interactions are stronger than hydrogen bonding because they involve full charges rather than partial charges.

To determine the order of intermolecular forces, you need to consider the molecular structure, polarity, electronegativity, and size of the molecules or ions involved. These factors influence the strength of the intermolecular forces present.