Question

at 25 degrees c, substances a and b have vapor pressures at 0.13 and 0.28 atm respectively. which of these substances have the higher boiling point?

I know the answer is substance A, but can someone explain why?

Answer 1

Vapor pressure : is the amount of gas in equilibrium with the liquid and solid phases. The higher the vapor pressure, the more gas in equilibrium, and thus the easier it is for the substance to vaporize and vice versa.

if the vapour pressure is more then the intermolecular forces are weak. so they can easily break. . so it requires less

energy . so low boiling point. if the vapour pressure is low then intermolecular forces are strong so they cant break easily so need more energy. so it has high boiling point.

Intermolecular forces are the attractive interactions between molecules. For something to vaporize, you have to get enough energy together to break these interactions. As a result, you'll need more energy (due to higher temperature) to break apart stronger intermolecular forces.

vapour pressure is high then the intermolecular forces are weak . so they can eas