Chapter 18, Problem 18.49QP

Interpretation Introduction

Interpretation:

To explain why $\text{HF}$ showing deviation from Trouton is’s rule.

Concept Introduction:

According to Trouton's rule for various liquids attheir boiling point the change in entropy value will be the same.

${\text{ΔS}}_{\text{vap}}\text{=}\frac{{\text{ΔΗ}}_{\text{vap}}}{{\text{T}}_{\text{bp}}}\approx {\text{90JK}}^{\text{-1}}{\text{mol}}^{\text{-1}}$

Where,

${\text{ΔS}}_{\text{vap}}$ is the entropy of vaporization

${\text{ΔΗ}}_{\text{vap}}$ is the enthalpy of vaporization

${\text{T}}_{\text{bp}}$ boiling temperature

Hydrogen bonding is the weak force of attraction between hydrogen and another electro negative atom.  When there is a hydrogen bonding interaction in the system, the entropy of the system will decrease.