I've had boiling explained to me in two ways, and I'm having trouble understanding how they connect.
The first way is that a liquid is held together by the intermolecular forces, and boiling involves breaking those bonds/interactions. This explains why, for instance, the boiling point of water is higher than that of methane, but not why boiling point is pressure dependent.
The second way is in terms of vapor pressure. Boiling occurs when bubbles form, and in order for a bubble to form and not be crushed, its internal pressure must be equal to the atmospheric pressure. From this view, the boiling point is the temperature at which the vapor pressure equals the atmospheric pressure. This explains why boiling point drops as pressure drops.
My issue is understanding how these coexist. The way I think of it, the strength of the intermolecular interaction should be the same no matter the pressure, so the temperature to break those interactions should be constant. Also, you can boil a liquid just by lowering the pressure, but I don't see how this affects the intermolecular interactions in any way.