Colloids Properties.
Some important properties of colloidal solutions are listed below.
Heterogeneity.
A colloidal solution is heterogeneous though solute particles are invisible nether an ordinary microscope. They tin range the sack live on detected amongst the tending of an ultramicroscope.
Osmotic Pressure.
The osmotic pressure level of a colloidal solution is really pocket-sized because of the number of colloidal particles are pocket-sized every bit compared to a solution containing the same total of solute particles inwards a given book of solvent.
Filterability.
The colloidal particles tin range the sack overstep through ordinary filters. However, yesteryear the move of ultrafilters, it becomes possible, to filter colloidal particles.
Tyndall Effect.
"When a potent beam of lite is concentrated on a colloidal solution, the path of the beam is illuminated yesteryear colloidal particles. It is called the Tyndall effect." The colloidal particles absorb lite in addition to so scatter lite of shorted waves. Because of this reason, the path of the beam is illuminated yesteryear blueish lite in addition to becomes visible when observed from the other side. "The green of lite made visible throughout the colloid is called the Tyndallbeam or Faraday Tyndall-cone".
Colour.
The colloidal solution is commonly coloured due to the scattering number of particles. The color depends upon the size in addition to the nature of particles, e.g.
Brownian Movement.
"The suspended particles inwards a colloidal solution are inwards a constant rapid zig-zag motion. It is called Brownian movement".
It is because of unequal bombordment yesteryear the solvent molecules or the molecules of the dispersion medium, which has comparatively smaller sizes.
Cataphoresis.
Since colloidal particles acquit a charge, they displace towards respective electrodes when placed inwards an electrical field. "The migration of colloidal particles nether the influence of the electrical champaign is called cataphoresis". It is employed to decide the sign of the electrical accuse on the colloidal particles.
Electro Osmosis.
If the colloidal particles inwards sol are maintained inwards a stationary state, the dispersion medium
moves. "The motion of dispersion medium nether the influence of the electrical champaign is
known every bit electro-osmosis". This phenomenon has been used dewatering peat, moist clay,
drying dyes in addition to pastes.
Precipitation or Coagulation.
The atmospheric precipitation or coagulation of a colloidal solution tin range the sack live on brought nearly yesteryear the add-on of a pocket-sized total of an electrolyte, e.g., a few drops of barium chloride to arsenious sulphide precipitate it. This is because of the argue that ions of electrolyte are absorbed yesteryear the colloidal particles. These shape bigger aggregates in addition to settle downwards every bit precipitate. In our example, sol particle beingness negatively charged, are neutralized by Ba+2 ions in addition to shape a precipitate.
Hardy-Schulze law.
It is concerned amongst the mightiness of an ion to coagulate a sol, It tin range the sack live on stated as. "The higher the valency of the active ion, the greater is its precipitating action", e. g. the precipitating activity of cations Na+, Mg2, and Al3+ is of the Order.
Na+ < Mg2+ < Al3+
Protection.
"The procedure yesteryear which the sole particles are protected from atmospheric precipitation yesteryear electrolytes due to the previous add-on of about hydrophilic colloid is called protection" The colloid added for protection is called a protective colloid. e.g., if a piffling gelatin is added to aureate sol, it is non coagulated yesteryear the add-on of sodium chloride. In this case, gelatin is a protective colloid.
The protective colloid particles shape a protective layer nearly sol particles in addition to hence forestall their precipitation.
Adsorption.
The particles at the surface of a company or liquid acquit repose valencies. In gild to satisfy it, they attract other particles in addition to retain at their surfaces. "This physical contact at the surface, betwixt ii particles, is called adsorption", The large surface offered yesteryear colloidal particles in addition to their costless valencies are responsible for adsorption yesteryear colloids.
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