Explain the formation of holes in Semi Conductors?
admin As we know that the forbidden energy gap in case of semiconductors is very small. At the temperature of zero Kelvin no electron will leave the valence band. So, conduction…
Define adsorption? What is the difference between adsorption and absorption?
Adsorption: The phenomenon of attracting and retaining the molecules of a substance on the surface of a liquid or a solid resulting into a higher concentration of the molecules on…
Distinguish between Physical Adsorption and Chemisorption?
Difference between physical adsorption and chemisorption are as following: PHYSICAL ADSORPTION CHEMISORPTIONS The forces operating in these are weak vander Waal’s forces. The forces operating in these cases are similar…
What do you mean by positive and negative adsorption?
Positive adsorption: In case of adsorption by solids from the solutions, mostly the solute is adsorbed on the surface of the solid adsorbent so that the concentration of solute on…
Discuss the factors affecting adsorption of gases by solids
Factors Affecting Adsorption of Gases by Solids: Almost all the solids adsorb gases to some extent. However, the exact amount of a gas adsorbed depends upon a number of factors,…
Why heat of adsorption is negative? Discuss the free energy change during adsorption.
Adsorption involves attracting molecules of adsorbate on surface of the adsorbent. Due to this, energy is released and thus heat of adsorption is negative i.e. adsorption is always exothermic. Further…
What are the applications of Adsorption?
Adsorption finds extensive applications both in research laboratory and in industry. A few applications are discussed below: In preserving vacuum: In Dewar flasks activated charcoal is placed between the walls…
What is the difference between Lyophilic and Lyophobic Sols?
Differences between lyophilic and lyophobic sols are as follows: PROPERTIES LYOPHILIC SOLS LYOPHOBIC SOLS Ease of preparation Prepared easily by directly mixing with the liquid dispersion medium. Cannot be prepared…
What do you mean by colloidal dispersion? What are its various types?
When some solid is dispersed into a medium in which the solid substance is otherwise insoluble such that after dispersion, the size of the colloidal particles lies in the colloidal…
What do you mean by peptization? What is the cause of peptization? Peptization:
Peptization is a process of passing of a precipitate into colloidal particles on adding suitable electrolyte. The electrolyte added is known as peptizing agent. A few examples of sols obtained…