Chapter 23.3, Problem 16R

To determine

To Explain: The process of fractional distillation.

Explanation of Solution

Introduction: The process of fractional distillation is used to separate components of a liquid mixture.

In fractional distillation, miscible liquids are separated because of their boiling points.

In a laboratory, a fractionating column, distillation flask, condenser, receiver, thermometer and a heat source is used to carry out the process of fractional distillation. Setting up the apparatus, a two-liquid mixture to be separated is taken in the distillation flask and heated. The mixture boils, with vapors rising in the flask. The liquid that has a lower boiling point evaporates through the fractionating column into the condenser and collects in the receiver. The liquid with a higher boiling point remains in the distillation flask.

Components of crude oil are separated using the process of fractional distillation. In refineries, fractionating towers are used. The towers have various metal chambers. Crude oil is added in the lowest chamber and heated using high-pressure steam. The mixture of boils and vapor is formed. The chambers in the tower have holes in their plates through which vapor passes to the various upper chambers. Components with the highest boiling point condense in the lower part of the tower while those with the lowest boiling point condenses at the top. The temperature is kept low at the top of the tower. Some components never condense at all and are collected as gases at the top. Hydrocarbons having large carbon-chains have a high boiling point, whereas, small hydrocarbons have lower boiling points.

Conclusion: The process of fractional distillation separates liquids based on their boiling points.