Which of the following is an example of an intermolecular force?

Hydrogen bonds are a specific type of intermolecular force that occur when a hydrogen atom covalently bonded to a highly electronegative atom, such as oxygen or nitrogen, experiences an attraction to another electronegative atom nearby. This unique interaction is particularly significant in biological systems, such as in the structure of water and in the formation of secondary structures in proteins like alpha-helices and beta-sheets.

While both van der Waals forces and hydrogen bonds are indeed intermolecular forces, the emphasis on hydrogen bonds in this context highlights their critical role in biological macromolecules and their impact on molecular interactions. In contrast, metallic bonds and covalent bonds are intramolecular forces that occur within a molecule or a metallic structure rather than between different molecules. Therefore, recognizing hydrogen bonds as an example of intermolecular forces is crucial for understanding their function in various biological processes.