SureDenColloidal State
Colloidal State:-
Thomas Graham classified the substances on the basis of their diffusion through the animal or vegetable membrane (SPM). The aq. Solution of which substances passed through the SPM were called Crystalloids and the substance whose aqueous solution do not pass through the SPM were called colloids. But this classification could not work a long, as the same substance can behave as crystalloid and colloids under different conditions. e.g. sodium chloride behaves as crystalloid in water while colloid in benzene. Hence it is stated that crystalloid and colloid are not the classification of substances but are states of the substance.
(1) True Solution (2) Colloidal Solution (3) Suspensions
These are discussed as below:-
|
Property |
True solution |
Colloidal solution |
Suspension |
|
Less than 1 nm (<10-9 m or 10A°) |
Between 1-1000nm (10-9 to 10-6m or 10-10000A°) |
More than 1000m (>10-6m or 10000A°) |
|
Pass through ordinary filter paper as well as animal membrane. |
Pass through ordinary filter paper but not through animal membrane. |
Do not pass through filter paper or animal membrane. |
|
Do not settle |
Do not settle |
Settle on standing |
|
Particles are not visible |
Particles are detected by ultra microscope. |
Particles are visible by naked eye or microscope |
|
Diffuse quickly |
Diffuse slowly |
Do not diffuse |
|
Clear and transparent |
Translucent |
Opaque |