Humber Admissions Practice Test

What describes the attraction between oppositely charged regions of polar molecules?

1. Metallic bonding

2. Dispersion forces

3. Dipole-dipole forces

4. Intramolecular forces

The correct answer is: Dipole-dipole forces

The attraction between oppositely charged regions of polar molecules is best described by dipole-dipole forces. These forces occur due to the presence of permanent dipoles in polar molecules, where one end of the molecule has a partial positive charge and the other end has a partial negative charge. This creates an electrostatic attraction between molecules, where the positive region of one polar molecule attracts the negative region of another. This interaction significantly influences the physical properties of substances, such as boiling points and solubility. Stronger dipole-dipole interactions typically result in higher boiling points. These forces are particularly pronounced in molecules with highly electronegative atoms, such as fluorine, oxygen, or nitrogen, which create significant charge separations within the molecules.