Intermolecular Forces and Why Boiling Points Behave Strangely

Boiling point questions look varied but nearly all reduce to one comparison: which intermolecular forces must be overcome, and how strong are they?

Identify the dominant force first — London forces, permanent dipole-dipole or hydrogen bonding — then compare molecular size and surface contact for London forces.

Water is the classic case: small, light, and yet with an unusually high boiling point, because hydrogen bonding dominates over molecular mass.