Chapter 17, Problem 98AE

Interpretation Introduction

Interpretation: The molar mass and vapor pressure of solution of sodium diatrizoatein pure water needs to be determined, if the vapor pressure of pure water at 31.2°C is 34.1 torr.

Concept Introduction:When a non-volatile solute is dissolved in solvent to get solution, the vapor pressure decreases for the solution and it can be calculated with the help of Raoult’s law that states that the vapor pressure of solution is the product of mole fraction of solvent and vapor pressure of pure solvent. When a volatile solute is added to the solvent, the overall vapor pressure of solution will be the sum of vapor pressure contribution of individual component.

The mathematical expression can be written as:

  ${\text{P}}_{\text{solution }}{\text{= [χ}}_{\text{A}}{\text{× P}}_{\text{A}}]+{\text{[χ}}_{\text{B}}{\text{× P}}_{\text{B}}]$