Question

The kinetic activity of colloidal particles suspended in liquid is known as:
A.Electro-osmosis
B.Cataphoresis
C.Brownian motion
D.Electrophoresis

Answer 1

When a solute substance such as gum dissolved in water, then a homogeneous solution results. The particle size, in this case, is found to be greater than that of the solute molecule in true solution and smaller than that of the suspensions. Such a solution is a colloidal solution and its particle size is in between $1m\mu - 0.1\mu$. The size of the colloidal particles is less than the wavelength of the visible light microscope.

Complete step by step answer:
Now we will discuss the given options one by one.
-The first option is Electro-osmosis. Electro-osmosis is the movement of the dispersion medium under the influence of the electric field when the dispersed particles are prevented from moving by some suitable means. It is the reverse of electrophoresis. It can be used in the dewatering of moist clay, drying of dye pastes, and the removal of the water from the peat.
-The second option is Cataphoresis. . When an electric current is passed through a colloidal solution, colloidal particles move towards either cathode or anode depending on their charges. The migration of the colloidal particles under the influence of the electric field is called Electrophoresis or cataphoresis.
-The third option is the Brownian motion. It has been observed that through an ultramicroscope that in colloidal solutions, particles are in a constant rapid zig-zag motion, called the Brownian movement. The phenomenon was observed by Sir Robert Brown. Brownian movement is a direct demonstration of the ceaseless motion of molecules as pictured by kinetic theory.
-The fourth option is Electrophoresis. When an electric current is passed through a colloidal solution, colloidal particles move towards either cathode or anode depending on their charges. When there is migration of the colloidal particles under the influence of the electric field is called Electrophoresis or cataphoresis.
-Cataphoresis is the other name of Electrophoresis. It is used to determine the charge on the colloidal particles.
Thus, the correct option is (C).

Note:
-A colloidal solution is heterogeneous. It consists of two phases:
-Dispersed phase- The extremely small particles which are dispersed in the solvent from a dispersed phase of silver in water.
-Dispersion medium- The solvent in which the particles are dispersed forms a dispersion medium. It is generally the component which is present in excess.