What characteristic of a molecule increases its ability to form hydrogen bonds?

The ability of a molecule to form hydrogen bonds is significantly influenced by the presence of lone pairs. Hydrogen bonds occur when a hydrogen atom is covalently bonded to a highly electronegative atom, such as oxygen, nitrogen, or fluorine. These electronegative atoms not only attract the hydrogen’s partial positive charge, but they also possess lone pairs of electrons that can participate in hydrogen bonding.

When we consider a molecule with lone pairs, such as water (H2O), the oxygen atom has two lone pairs. These lone pairs can interact with hydrogen atoms from other molecules, allowing for the formation of hydrogen bonds. This interaction is crucial for the properties of water, such as its high boiling point relative to other molecules of similar size, and is fundamental in biological systems, impacting the structure and function of proteins and nucleic acids.

While low electronegativity would decrease the tendency to form hydrogen bonds (since a less electronegative atom would not effectively attract the hydrogen’s partial charge), high molecular weight does not necessarily correlate with an increased ability to form hydrogen bonds. Similarly, high temperature can provide kinetic energy that may disrupt existing hydrogen bonds rather than promoting their formation. Therefore, the presence of lone pairs is essential for enhancing a molecule's