Monday, October 29, 2012

Difference Between Lyophilic and Lyophobic Colloids

S.No.
PROPERTY
LYOPHILIC COLLOIDS
LYOPHOBIC COLLOIDS
1.
Mode of preparation.
Forms easily by mere shaking or warming the dispersed phase with dispersion medium E.g. Gelatine in water.
Forms only by special methods.
Example: AS2S3 in water.
2.
Size of particle
The particles are true molecules and are just bigger in size (Molecular colloids).
The particles are aggregates of thousands of molecules (Associated colloids).
3.
Nature
Reversible and once precipitated can readily pass into colloidal state by direct contact with dispersion medium because particles are solvent loving.
Irreversible and once precipitated can not easily pass into colloidal state because particles are solvent hating.
4.
Visibility
The particles are not easily detected even under ultra microscope.
The particles are easily detected under ultra microscope.
5.
Charge
The charge of particles depends upon PH of medium and it may be positive, negative or neutral.
The particles carry positive or negative charge.
6.
Stability
These are stable and are self – stabilized.
These are unstable and hence require traces of electrolyte for stabilisation.
7.
Action of electrolytes
Co-agulation can be brought about by the addition of large amount of electrolyte.
Co-agulation can be brought about by small amount of electrolyte.
8.
Viscosity
It is much higher than that of dispersion medium.
It is about same as that of dispersion medium.
9.
Surface
It is lower than dispersion medium
It is about same as that of dispersion medium.
10.
Tyndall effect
Less distinct
More distinct.
11.
Electrophoresis
The particles may or may not show electrophoresis.
The particles show electrophoresis.
12.
Hydration
The particles are heavily hydrated due to love for solvent.
The particles are not appreciably hydrated due to hate for solvent.
13.
Conc. Of dispersed phase
Higher concentrations of dispersed phase are possible.
Only low concentrations of dispersed phase are possible.
14.
Colligative property
They have relatively high osmotic pressure, depression in freezing point and high lowering in vapour pressure.
They have high osmotic pressure, less depression in freezing point, less elevation in boiling point and less lowering of vapour pressure.

2 comments:

  1. definitions??????????????????????/

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  2. Colloids are mixtures which have particle size larger than 1nm and less than 1000nm.Solvent loving colloids are called lyophilic colloids and solvent hating colloids are called lyophobic colloids.

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