Chapter 14, Problem 113A

Interpretation Introduction

Interpretation:

The change of ?T_b and ?T_f for the solution of non-electrolytes and electrolytes needs to be described.

Concept introduction:

Elevation of boiling point: When a solute is added to a solvent, the boiling point of a solution, will be greater than the boiling point of the pure solvent.

For nonelectrolytes, the value of the boiling point elevation, which is symbolized ? T_b, is directly proportional to the solution’s molality.

Boiling point elevation $\Delta {\mathrm{T}}_b=K_b\times m$

Depression of freezing point: When a solute is added to a solvent, the freezing pointof a solution, will be lower than the freezing pointof the pure solvent.

For nonelectrolytes, the value of the depression of freezing point, is directly proportional to the solution’s molality.

Depression of freezing point $\Delta T_f=K_f\times m$

Answer to Problem 113A

The values of ? T_b and ? T_f are higher for electrolytes than non-electrolytes as the electrolyte solutes dissociate in aqueous solution to give ions. So, the number of solute particles in electrolyte solution are greater than the particles innon-electrolyte solution. As, the colligative properties of the solution is directly linked to the number of particles in the solution, ? T_b and ? T_f will be greater for electrolytes.

Explanation of Solution

The given figure displays the differences in boiling and freezing points of pure solvent and the solution. Upon addition of non-electrolyte or electrolyte solute, the boiling point of the solution increases and the freezing point of the solution decreases. The values of ?T_b and ?T_fare higher for electrolytes than non-electrolytes as the electrolyte solutes dissociate in aqueous solution to give ions. So, the number of solute particles in electrolyte solution are greater than the particles innon-electrolyte solution. As, the colligative properties of the solution is directly linked to the number of particles in the solution, ? T_b and ? T_fwill begreater for electrolytes.