Chapter 17, Problem 116AE

Interpretation Introduction

Interpretation:

The K_a for a 0.100 g sample of weak acid HA with a freezing point of -0.0056 C needs to be deduced.

Concept Introduction:

The depression in freezing point ( ${\text{ΔT}}_{\text{f}}$ ) of a solution in the presence of a solute of molality ( m ) is given as:

  $\begin{array}{l}{\text{ΔT}}_{\text{f}}{\text{ = T}}_{\text{f}}^{\text{0}}-{\text{ T}}_{\text{f}}\\ {\text{ΔT}}_{\text{f}}{\text{=i(K}}_{\text{f}}\text{×m) -----(1)}\end{array}$

Here,

  ${\text{T}}_{\text{f}}^{\text{0}}$ and ${\text{T}}_{\text{f}}$ are the freezing points of the pure solvent and solution respectively. K_f denotes the freezing point depression constant and i represents the Von’t Hoff factor.