Chapter 12, Problem 107RQ

Interpretation Introduction

Interpretation:

The von’t Hoff factor for LiCl at $0.118\text{ m}$ solution at ${\text{10 }}^0\text{C}$ and the osmotic pressure in torr is to be determined.

Concept Information:

The van't Hoff factor is defined as the ratio between the actual concentration of particles formed when the substance is dissolved and the concentration of the constituent as interpreted from its mass.

For most of the non-electrolytes that are dissolved in water, the van't Hoff factor is, generally, $1$

. 

The freezing points of solutions are all lesser as compared to the pure solvent and are directly related to the molality  of the solute.

$\begin{array}{c}\Delta T_f=T_f\text{(solvent)}-T_f\text{(solution)}\\ =i\times K_f\times m\end{array}$

Here, $\text{Δ}{T}_f$ is the freezing point depression, $T_f\text{(solution)}$ is the freezing point of the solution, $T_f\text{(solvent)}$ is the freezing point of the solvent, $K_f$ is the freezing point depression constant, and $m$

 is the molality.

Osmotic pressure can be expressed by following equation:

$\Pi =iM\text{R}T$

Here, $\Pi$ is the osmotic pressure, $i$ is the von’t Hoff factor, $\text{M}$ is the molality, $R$ is the gas constant and $\text{T}$ is the temperature.