Chemistry Handbook-Surface Chemistry Handbook PDF

Surface Chemistry Handbook PDF.

Surface chemistry handbook PDF Download


Surface chemistry handbook is very useful for quick revision of formula and definition are given in the Surface Chemistry chapter. This Handbook is designed according to the syllabus of JEE Main and Advance. 

This Surface chemistry handbook PDF is very useful for the Students preparing for JEE Main and Advance. Download the handbook PDF and revise the chapter in just 4 min.
Download the PDF of Surface Chemistry Handbook from the link Given Below.

Classification based on the interaction of phases:

LYOPHILIC AND LYOPHOBIC SOLS.

Colloidal solutions in which the dispersed phase has considerable affinity for the dispersion phase, are called lyophilic sots (solvent - liking).

For example - dispersion of gelatin, starch, gum and proteins in water. Colloidal solutions in which the dispersed phase has no affinity or attraction for the medium or for the solvent are called Lyophobic colloidal (Solvent hating) solutions.

Comparison of Lyophobic and Lyophilic Sols.

Properties Lyophilic Sol Lyophobic Sol
Preparation Can not be prepared easily prepared by saking or warming the substance with solvent. Can not be prepared easily special methods are required.
Stability Are more stable Are less stable
Reversibility Are reversible Are irreversible
Viscosity viscosity is much higher than that of solvent. viscosity is nearly same as that of solvent
Surface Tension Surface tension is usually low. Surface Tension is almost same as that of solvent
Hydration These are highly solvated as the particles have great affinity for solvent These are less solvated as the particles have less affinity for the solvent
Charge The particles have little charge or no charge at all. The Particles carry a characteristic charge either positive or negative.
Visibility particles can not be seen under microscope. Particles can be seen under microscope.
Coagulation Precipitated by high concentration of electrolytes. Precipitated by low concentration of electrolytes.
Tyndall effect Less Scattering. More Scattering.
Migration in Electric field May or may not migrate as they may or may not carry charge. Migrate towards anode or cathode as these particles carry charge.
Examples Mostly of organic nature- Gelatin, starch, Gum Mostly of Inorganic - Transton metal, Gold,As.


PEPTIZATION

The dispersion of a freshly precipitated material into colloidal solution by the action of an electrolyte in solution is termed as peptization. The electrolyte used is called a Peptizing agent.

Hardy Schulze Rule - This rule states that the precipitating effect of an ion on the dispersed phase of opposite charge increases with the valency of the ion.
The higher the valency of the flocculating ion, the greater is its precipitating power.
Thus for the precipitation of As2S3 sol (-ve), the precipitating power of A3+, Ba2-, and Na+ ions is in the order.
The minimum concentration of an electrolyte in millimoles required to cause precipitation of 1-liter sol in 2 hours is called FLOCCULATION VALUE. The smaller the flocculating value, the higher will be the coagulating power of the ion.

Flocculation value is proportional 1 / Flocculation power.


GOLD NUMBER
The number of milligrams of a hydrophilic colloid that will just prevent the precipitation of 10 ml of standard gold sol on the addition of 1 ml of 10% NaCI solution is known as the Gold number of that protector (Lyophilic colloid).
The precipitation of the gold sol is indicated by a color change from red to blue when the particle size just increases.
The smaller the gold number of a protective Lyophilic colloid, greater is its protection power.

Protection Capacity is proportional to 1/ a Protection Number (Gold number).

Note: Gelatin is best protecting colloid because it has a least gold number.

Types of colloids according to their Size

Multi Molecular
Formation by aggregation of a large number of atoms or smaller molecules of substance
Examples- Gold Sol, Sulphur sol.

Macro Molecular
Formation by aggregation of big size molecules. These are polymers with high molecular mass.
Examples- Starch, Protein

Associated Colloids
These are the substances which behave as normal electrolytes as normal electrolytes at low concentration but get associated at higher concentration and behave as colloidal solution .these associated particles are also called micelles.
Example- Soap & Detergent.

Comparison of Physical Adsorption and Chemical Adsorption.


Physical adsorption Chemical Adsorption
It is caused by intermolecular vander waal forces it is caused by chemical bond formation.
It is not specific. It is highly specific.
It is reversible. It is not reversible.
Heat of adsorption is low -20 to -40 kJ/mol Heat of adsorption ic high -80 to -240 KJ/mol
No appreciable activation energy is involved. High activation energy is involved
It forms multimolecular layers on adsorbent surface. It forms unimolecular layers under high pressure.


Critical temperature increases.
Ease of liquefication increases.
The extent of adsorption increases.

General characteristics of catalysts.

(1) Catalyst remains unchanged in mass and chemical composition but can change their physical state.
(ii) Only a very small amount of catalyst is sufficient to catalyze a reaction.
(iii) A catalyst does not initiate a reaction.
(iv) Solid catalyst is more efficient when used in the finely divided form.
(v) Generally, the catalyst does not change the nature of products.
(vi) A catalyst does not change the equilibrium state of a reversible reaction but helps to achieve the equilibrium state Or position of equilibrium in lesser time.
(vii) The catalyst is generally specific in nature.
(viii) Change rate constant of the reaction.
(ix) Does not change free energy of the reaction.
(x) Participate in the mechanism of the reaction.


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by- Shikhar Pandey
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