Which term describes the pressure exerted by a vapor in equilibrium with its liquid at a given temperature?

• A. Partial pressure
• B. Atmospheric pressure
• C. Vapor pressure
• D. Osmotic pressure

Answer: (C)

Verified step by step guidance

1. Understand that when a liquid and its vapor are in equilibrium at a given temperature, the vapor exerts a specific pressure known as vapor pressure.
2. Recall that vapor pressure is the pressure exerted by the vapor molecules above the liquid when the rate of evaporation equals the rate of condensation.
3. Recognize that partial pressure refers to the pressure of a single gas in a mixture, which is different from vapor pressure that specifically relates to the equilibrium between liquid and vapor phases.
4. Note that atmospheric pressure is the pressure exerted by the weight of the atmosphere, and osmotic pressure relates to the pressure required to stop osmosis, so neither describes the pressure of vapor in equilibrium with its liquid.
5. Conclude that the correct term for the pressure exerted by a vapor in equilibrium with its liquid at a given temperature is vapor pressure.