What structural feature in a molecule is indicative of potential hydrogen bonding?

The presence of O-H or N-H bonds in a molecule is indicative of potential hydrogen bonding due to the specific characteristics of these bonds. Hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom, such as oxygen or nitrogen, experiences an attractive force with another electronegative atom's lone pair.

In the case of an O-H bond, oxygen is highly electronegative and pulls the bonding electrons towards itself, resulting in a partial negative charge on the oxygen and a partial positive charge on the hydrogen. Similarly, N-H bonds exhibit a considerable dipole due to nitrogen's electronegativity. The presence of these polar bonds creates an environment where hydrogen bonds can form with other molecules or within different parts of the same molecule, promoting interactions such as solubility in water or increased boiling points in substances with such bonds.

Other structural features mentioned, such as double bonds, carbon chains, and aromatic rings, do not inherently facilitate hydrogen bonding. While double bonds can influence other types of molecular interactions, they do not provide the necessary functional groups for hydrogen bonding. Carbon chains and aromatic rings mainly contribute to the overall structure and properties of molecules but lack the specific polar interactions that enable hydrogen bonding.