Chapter 14, Problem 119E

Interpretation Introduction

Interpretation:

Consider a 100 mL of solution with 13.5% of NaCl by mass with a density of 1.12$\frac{\text{g}}{\text{mL}}$ . What among solute and solvent and how much we need to add to given solution to make the boiling point of solution104.4°C (take i=1.8).

Concept introduction:

a) The percentage by mass means that that amount of solute is dissolved in 100 g of solution.

b) The elevation in boiling point is a colligative property and is related to molality as

∆T_b = i.K_b.m

where,

∆T_b is change in boiling temperature

i is Van’t Hoff factor

K_b is molal boiling-point elevation constant

m is molality

Given:

The density of solution is 1.12 $\frac{\text{g}}{\text{mL}}$

Volume of solution is 100 mL

Mass percentage of NaCl is 13.5 %

Van’t Hoff factor = i = 1.8