Chapter 15, Problem 15.152QP

Interpretation Introduction

Interpretation: We cannot use osmotic pressure to determine both molar mass and percent ionization for unknown monoprotic acid has to be explained.

Concept introduction

Colligative properties depend only on the number of solute particle present, does not depend on type of the particle. Thus particle may be ions or molecules. If the particle may ions, the essential aspect is sum of the concentration of anions and cations. That is ‘Colligative’ represents collection of particle. Example for colligative properties,

• Boiling point elevation
• Freezing point depression
• Vapor pressure lowering
• Osmotic pressure

Osmotic pressure is the pressure that is needed to stop osmosis. Osmotic pressure of the solution is directly proportional to the concentration of the solution. We can calculate osmotic pressure by using this formula is given by,

$\text{π = iMRT}$

Where,

$\begin{array}{l}\text{π- Osmotic pressure}\\ \text{i- van't Hoff factor}\\ \text{M- Molarity of the solution(mol/L)}\\ \text{R- Universal gas constant}\\ \text{T- Temperature (Kelvin)}\end{array}$

Percent ionization: At particular concentration quantity of weak acid survive as ions known as percent ionization. This is calculated by using the formula is,

$\text{percent ionization =}\frac{\left[{\text{H}}^{\text{+}}\right]}{\text{HA}}\text{×100\%}$

Molar mass: Molar mass is defined as mass of the chemical compound or chemical element divided by its amount.

$\text{molar mass = }\frac{\text{mass of the substance in grams}}{\text{moles}}$