Chapter 18, Problem 67SCQ

Interpretation Introduction

Interpretation:

The temperature at which equilibrium constant for the given reaction is one and the temperature at which vapor pressure is $\frac{1}{760}\text{ bar}$ should be estimated. The temperature used for $P=1bar$ should be identified.

Concept introduction:

The vapor pressure of a substance is related to its enthalpy of vaporisation by the

expression,

  $\text{ln}\left(\frac{{\text{p}}_{\text{2}}}{{\text{p}}_{\text{1}}}\right)\text{=}\frac{{\text{ΔH}}_{\text{vap}}}{\text{R}}\left(\frac{\text{1}}{{\text{T}}_{\text{1}}}\text{-}\frac{\text{1}}{{\text{T}}_{\text{2}}}\right)$

Here, ${\text{p}}_{\text{1}}$ and ${\text{p}}_{\text{2}}$ are the vapour pressures at two different temperatures ${\text{T}}_{\text{1}}$ and ${\text{T}}_{\text{2}}$.

This equation is known as Clausius-Clapeyron equation and is used to estimate the vapor pressure of a substance at a particular temperature.