What type of intermolecular force is the strongest and usually leads to high boiling points?

Hydrogen bonding is the strongest type of intermolecular force listed in the options and is responsible for significantly elevated boiling points in substances that can engage in this type of bonding. This interaction occurs when hydrogen is bonded to highly electronegative atoms like nitrogen, oxygen, or fluorine. The hydrogen atom, being partially positive due to the electronegativity of the atom it is bonded to, can interact strongly with the lone pairs of electrons on nearby electronegative atoms.

This strong attraction results in a greater amount of energy being required to separate the molecules, thus leading to higher boiling points. For instance, water, which exhibits hydrogen bonding, has a boiling point of 100 degrees Celsius, much higher than would be expected based on its molecular weight alone. Other types of intermolecular forces, such as dipole-dipole interactions and London dispersion forces, are weaker by comparison and do not lead to such high boiling points. Ionic bonding typically occurs in solid crystalline structures and involves the electrostatic attraction between oppositely charged ions, which governs melting points rather than boiling points in molecular substances.