Adsorption
Chapter Name : Surface Chemistry |
Sub Topic Code : 102_12_05_02_02 |
Topic Name : Adsorption |
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Sub Topic Name : Distinction Between Adsorption And Absorption |
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Introduction
• Adsorption is a surface phenomenon. It describes the attraction and retention of the molecules of a substance on the surface of solid. • Absorption is a bulk phenomenon. It describes the penetration of a substance from the surface of solid to the bulk. • When both absorption and adsorption occur simultaneously, it called as sorption.
Pre-Requisites:
Distinction Between Adsorption And Absorption
Activity:
Dip a piece of chalk in blue dye. You will see that its outer surface turns blue while the inner surface remains white in colour.
Real Life Question:
When a piece of chalk is dipped in blue dye, why does its outer surface turn blue while the inner surface remains white?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Adsorption | It is the phenomenon of accumulation of molecules of a liquid/gas on the surface of a solid. |
| Absorption | It is the process by which 1 substance (solid /liquid), takes up another substance (liquid/gas), through minute pores or spaces between its molecules. |
| Sorption | When both adsorption and absorption occur simultaneously, it is called as sorption. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| White chalk piece | Dip a piece of chalk in blue dye. |
| Blue dye | For dipping the chalk. |
Real life uses :
Dyeing.
Places to visit :
A dye shop- dyeing of a piece of cloth involves both adsorption and absorption.
Practical examples around us
| Examples | Explainations |
|---|---|
| Dyeing of cloth | Dyeing involves both adsorption and absorption. Adsorption ensures that the dye is retained on the cloth surface while absorption ensures that the dye goes into the cloth pores for a long lasting effect. |
What you learn in Theory:
The difference between the phenomena of adsorption and absorption.
What you learn in Practice:
Usage of both the processes simultaneously.