Lyophobic sols are unstable and are easily precipitated by the addition of electrolytes. However it is observed that the addition of certain lyophilic colloids like gums, soaps, gelatin etc. To lyophobic colloids render lyophobic colloids difficult to coagulate by the addition of electrolytes. The process ...

Coagulation can be caused by the following methods: By electrophoresis: In electrophoresis, the particles of dispersed phase move towards oppositely charged electrode and get neutralized. If the process is continued for sufficient time, these neutral particles unite and grow in size and settle down. By mutual precipitation: Mutual ...

Coagulation: Coagulation is a process which involves coming together of colloidal particles so as to change into large sized particles which ultimately settle as a precipitate or float on the surface. Coagulation is generally brought about by the addition of electrolytes. When an electrolyte is added ...

On placing a colloidal solution under the influence of an electric field, the particles of the dispersion medium move towards oppositely charged, provided the colloidal particles are not allowed to move. This phenomenon is called electro-osmosis. Hence, Electro-osmosis may be defined as a phenomenon in which the ...

The existence of the electrical charge can be shown by the process of ‘Electrophoreses’ which is also known as ‘Cataphoresis’. It involves the movement of colloidal particles towards one or the other electrode when placed under the influence of an electric field. The movement of ...

The various reasons for the origin of electrical charge on the colloidal particles are as follows: Frictional electrification: It is caused by the mutual rubbing of colloidal particles with molecules of the dispersion medium. Electron capture: Electron capture by particles from air and during electro dispersion in Bredig’s arc ...

Comparisons of multimolecular, macromolecular and associated colloids are as follows: MULTIMOLECULAR COLLOIDS MACROMOLECULAR COLLOIDS ACCOCIATED COLLOIDS They are formed by the aggregate of a large number of atoms or molecules which generally have diameters less than 1nm, e.g. Sols of gold, sulpher etc. They are molecules ...

Physical properties of colloidal solutions: Heterogeneous character: Colloidal particles being larger than molecules form heterogeneous mixture composed of particles of dispersed phase and dispersion medium. The phenomenon of Tyndall effect, electrophoresis and electro-osmosis confirm heterogeneity of colloidal systems. Stability: Colloidal sols are quite stable. Only a few colloidal particles ...

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 by peptization are given below: A reddish brown colored colloidal solution is obtained by adding small ...

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 range, the system is called a colloidal dispersion. Examples of colloidal dispersion are gold sol, ...