Now it's time to relate the indirect relationships that we have between intermolecular forces in a particular physical property. So we're going to say here under indirect relationships, the stronger the intermolecular force, then the weaker the physical property. The physical property in question is vapor pressure.
Now, vapor pressure is just the pressure exerted by a gas at the surface of a liquid. And realize that vapor pressure is the result of an equilibrium between condensation and vaporization. So the gases on top basically pushed down on the liquid creating a vapor pressure.
And we're going to say here the stronger the intermolecular force, the weaker the vapor pressure or lower the vapor pressure will be for substance. So they are basically indirectly related or opposites of one another. One is high, the other one is low. Stronger intermolecular force translates to a lower or weaker vapor pressure.