Question

The relationship between the vapor pressure and the absolute temperature of a liquid is expressed by

• A. Biles Equation
• B. Lien and Kennon Equation
• C. Joule-Thomson Equation
• D. Clausius- Clapeyron Equation

Answer 1

The Correct Option is D

The question asks about the relationship between the vapor pressure and the absolute temperature of a liquid. To solve this question, we need to identify which equation is used to describe this relationship.

Let's analyze the options provided:

1. Biles Equation: This is not a commonly known equation in the context of vapor pressure and temperature. It is not relevant to this context.
2. Lien and Kennon Equation: This equation is not standard in the context of vapor pressure and temperature relations in physical chemistry or physical pharmacy.
3. Joule-Thomson Equation: This equation describes the Joule-Thomson effect, which relates to the change in temperature of a real gas when it is allowed to expand or compress at constant enthalpy. It is unrelated to vapor pressure.
4. Clausius-Clapeyron Equation: This equation describes how the vapor pressure of a liquid changes with temperature. It provides a way to quantify the vapor pressure at different temperatures assuming the enthalpy of vaporization is constant over the temperature range.

Based on the analysis above, the correct answer is the Clausius-Clapeyron Equation.

The Clausius-Clapeyron equation is expressed as:

\(\frac{dP}{dT} = \frac{L}{T(V_{\text{vapor}} - V_{\text{liquid}})}\)

Where:

• P is the vapor pressure.
• T is the absolute temperature.
• L is the latent heat of vaporization.
• V_{\text{vapor}} and V_{\text{liquid}} are the molar volumes of the vapor and the liquid, respectively.

This equation is crucial in understanding the phase transitions and is widely applied in various fields such as physical chemistry and engineering.