Chapter 13, Problem 13.110P

(a)

Interpretation Introduction

Interpretation:

The molality and van’t Hoff factor for the aqueous $\text{NaCl}$ solution are to be calculated.

Concept introduction:

Molality is the measure of the concentration of solute in the solution. It is the amount of solute that is dissolved in one kilogram of the solvent. It is represented by $\text{m}$ and its unit is moles per kilograms. The solute is the substance that is present in a smaller amount and solvent is the substance that is present in a larger amount.

The formula to calculate the molality of the solution is as follows:

$\text{Molality}=\frac{\text{amount}\left(\text{mol}\right)\text{of}\text{solute}}{\text{mass}\left(\text{kg}\right)\text{of}\text{}\text{solvent}}$ (1)

The formula to calculate the change in freezing point is as follows:

$\Delta T_{\text{f}}=i{k}_{\text{f}}m$ (2)

Here, $\Delta T_{\text{f}}$ is the change in freezing point.

$i$ is van’t Hoff factor.

$k_{\text{f}}$ is the freezing point depression constant.

$m$ is the molality of the solution.

The van’t Hoff factor is a measure of the effect of solute on the colligative properties. It is represented by $i$. It is defined as the ratio of measured values for the electrolytic solution to the expected values for non-electrolytic solutions. It is a unitless quantity.

(b)

Interpretation Introduction

Interpretation:

The molality and van’t Hoff factor for the aqueous ${\text{CH}}_3\text{COOH}$ solution are to be calculated.

Concept introduction:

Molality is the measure of the concentration of solute in the solution. It is the amount of solute that is dissolved in one kilogram of the solvent. It is represented by $\text{m}$ and its unit is moles per kilograms. The solute is the substance that is present in a smaller amount and solvent is the substance that is present in a larger amount.

The formula to calculate the molality of the solution is as follows:

$\text{Molality}=\frac{\text{amount}\left(\text{mol}\right)\text{of}\text{solute}}{\text{mass}\left(\text{kg}\right)\text{of}\text{}\text{solvent}}$ (1)

The formula to calculate the change in freezing point is as follows:

$\Delta T_{\text{f}}=i{k}_{\text{f}}m$ (2)

Here, $\Delta T_{\text{f}}$ is the change in freezing point.

$i$ is van’t Hoff factor.

$k_{\text{f}}$ is the freezing point depression constant.

$m$ is the molality of the solution.

The van’t Hoff factor is a measure of the effect of solute on the colligative properties. It is represented by $i$. It is defined as the ratio of measured values for the electrolytic solution to the expected values for non-electrolytic solutions. It is a unitless quantity.