Chapter 4, Problem 4.5P

Interpretation Introduction

Interpretation:

It should be determined that the normal boiling point of benzene given that its vapour pressure is 20 kPa at ${35}^{o}C$ and 50 kPa at $58.8{}^{o}C$.

Concept Introduction:

The Clapeyron equation is exact and applies rigorously to all first order phase transitions. Its derivation involves approximations, in particular the assumptions that the perfect gas law holds and that the volume of condensed phases can be neglected in comparison to the volume of the gaseous phase. It can be applies only to phase transitions between the gaseous state and condensed phases.

Clausius-Clapyron equation,

$\text{ln}\frac{{\text{P}}_{\text{2}}}{{\text{P}}_{\text{1}}}\text{=}\frac{{\text{ΔH}}_{\text{vap}}}{\text{R}}\left(\frac{\text{1}}{{\text{T}}_{\text{2}}}\text{-}\frac{\text{1}}{{\text{T}}_{\text{1}}}\right)\boxed{\begin{array}{l}\text{where,}\\ {\text{ΔH}}_{\text{vap}}:\text{Enthalpy}\text{of}\text{vaporization}\\ \text{R}:\text{Gas}\text{constant}\\ {\text{P}}_{\text{1}}:\text{VaporPressure}\text{at}{\text{temperatureT}}_{\text{1}}\\ {\text{P}}_{\text{2}}:\text{VaporPressure}\text{at}{\text{temperatureT}}_{\text{2}}\end{array}}$