Basic physical properties:

3. How do these forces affect boiling point?

Boiling point (BP) is the temperature at which a liquid boils and becomes a gas.

The basic rule: stronger intermolecular attractions generally mean a higher boiling point.

Why? Because more energy is needed to separate the molecules.

For compounds of similar size, a useful starting point is:

LDF only < Dipole–dipole < Hydrogen bonding

This is a simplified guide, not an absolute ranking for every molecule. Molecular size matters, too.

For example, a longer alkane can have a higher boiling point than a much smaller polar molecule because its LDF may be much stronger.