surface chemistry

defination

The branch of chemistry that deals with the phenomena that occurs at the

surfaces or the interfaces is known as Surface Chemistry. A lot of properties of

matter such as solids and liquids depend on the nature of the surface. Let us

learn introduction about Surface Chemistry through chemistry lecture notes.

Adsorption:

• The phenomenon of attracting and retaining the molecules of a substance at

the surface of a solid or a liquid resulting into higher concentration of the

molecules on the surface than in the bulk is known as adsorption. Adsorption

results in decrease of surface energy.

• Examples of Adsorption:

a) Adsorption of a gas by Charcoal: Finely grounded activated charcoal adsorb

a gases like ammonia, sulfur dioxide, chlorine, hydrogen, carbon monoxide,

phosgene. Charcoal is the adsorbent whereas the gas molecules acts ass adsorbate.

b) Adsorption of a dye by Charcoal: The dye gets adsorbed on the surface of

the animal charcoal when the animal charcoal is shaken with an organic dye

solution. For example, methylene blue. It turns colourless due to adsorption.

c) Air in presence of silica gel: Water molecules get adsorbed on the silica gel.

This make the air dry

• constituents of Adsorption Process:

The adsorption process consists of two types of substances:

1. Adsorbent: The solid substance on the surface of which adsorption occurs

is known as adsorbent. Adsorbent can be a solid or a liquid.

1. Adsorbate: The substance which gets adsorbed on the solid surface due to

intermolecular force of attractions is known as adsorbate. Adsorbate can

be a gas or a solute some solution.