Chapter 4, Problem 4E.3E

Interpretation Introduction

Interpretation:

The freezing point of $200c{m}^3$ of water which contains of $2.5g$ of $NaCl$ has to be estimated.

Concept introduction:

Colligative properties: properties of solutions which having influence on the concentration of the solute in it. Colligative properties are,

• Decrease in the vapour pressure
• Increase in the boiling point
• Decline in the freezing point
• Osmotic pressure

$\text{Molality}\left(\text{m}\right)\text{=}\frac{\text{Moles}\text{of}\text{solute}}{\text{Kilograms}\text{of}\text{solvent}}$

If molality and $K_f$ are known, then the freezing point of the solution can be calculated using the equation,

$\Delta T_f=im{K}_f\boxed{\begin{array}{l}i\to Vant-Hofffactor\\ m\to molality \\ \Delta {\text{T}}_f\to Depressioninfreezingpoint \\ k_f \to cryoscopiccons\tan t\end{array}}$

$Mass=Density\times volume$