[LHM]

A sample of water vapor in a flask is at a temperature of 65°C and a pressure of 80 mmHg. It's all water vapor, and none of the water vapor has condensed. If the flask is cooled to 45°C, will all of the liquid condense or only some of it? (Note: the vapor pressure of water at 65°C is 187 torr and at 45°C is 72 torr.)

My thought process was that all of it would condense since 72<80. However, the answer says that it will not completely condense. Is this because there's still some that exists as water vapor that gives rise the vapor pressure, which is 72 torr?

[Borek]

Yes, 72 torr has to be left and it will be in equilibrium with a liquid present.