Which statement about vapor pressure and temperature is true?

Which statement about vapor pressure and temperature is true?

• A. Vapor pressure generally decreases with temperature
• B. Vapor pressure generally increases with temperature
• C. Vapor pressure remains constant with temperature
• D. Vapor pressure is unpredictable with temperature

Answer: (B)

Vapor pressure increases with temperature because heating provides more molecules with enough energy to escape from the liquid into the vapor. As more molecules enter the vapor phase, they collide and exert pressure at the surface, raising the equilibrium vapor pressure. This upbeat trend continues as temperature rises, which is why boiling occurs when vapor pressure matches surrounding pressure. The other ideas—vapor pressure decreasing, staying constant, or being unpredictable with temperature—don’t align with how energy and phase change work in liquids.

Vapor pressure increases with temperature because heating provides more molecules with enough energy to escape from the liquid into the vapor. As more molecules enter the vapor phase, they collide and exert pressure at the surface, raising the equilibrium vapor pressure. This upbeat trend continues as temperature rises, which is why boiling occurs when vapor pressure matches surrounding pressure. The other ideas—vapor pressure decreasing, staying constant, or being unpredictable with temperature—don’t align with how energy and phase change work in liquids.