In an open system , the vapor pressure is equal to the outside air pressure. True False

False<br /><br />In an open system, the vapor pressure of a liquid is not necessarily equal to the outside air pressure. Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase at a given temperature. In an open system, the vapor pressure can be lower than the atmospheric pressure, and it only equals the atmospheric pressure when the liquid reaches its boiling point. At this point, the liquid will start to boil, as the vapor pressure is sufficient to overcome the atmospheric pressure.