Chapter 5, Problem 12Q

Interpretation Introduction

Interpretation:

The effect of the decrease in atmospheric pressure on the boiling point should be determined. Also, whether cyclohexane and toluene can be separated if the external pressure is $350\text{ mm Hg}$ instead of $760\text{ mm Hg}$ should be determined.

Concept introduction:

A technique used to separate various components or a fraction from a mixture based on their volatilities is called fractional distillation. The fractional distillation is used to separate different components of the mixture if boiling point difference is less than $75°\text{C}$. Fractional distillation is better than the simple distillation due to the low boiling point range. It is used to separate crude oil into useful substances in oil refineries.

The boiling point of the substance is that temperature value at which vapor pressure of the liquid is equal to the value of atmospheric pressure and the liquid changes into a vapor. It is a colligative property because it depends on a number of moles of solute particles that are present in the substance.