Question

Movement of colloidal particle after developing charge

• A. Brownian
• B. Osmosis
• C. Electrodialysis
• D. Electrophoresis

Hint:

Electrophoresis is a key characteristic of charged colloidal particles, directly linking their charge to their directed movement in an electric field. Brownian motion is random and independent of charge.

Answer 1

The Correct Option is D

Step 1: Analyze the key terms in the question.
The question asks about the "movement of colloidal particle after developing charge". This implies a specific type of motion that is a direct consequence of the particles acquiring an electrical charge. Step 2: Evaluate each option in the context of charged colloidal particle movement.
(A) Brownian movement: This refers to the continuous, random, zig-zag motion of colloidal particles. It is caused by the incessant and unequal bombardment of the colloidal particles by the molecules of the dispersion medium. While characteristic of colloidal dispersions, Brownian movement is primarily dependent on the size of the particles and the viscosity of the medium, not directly on the charge of the particles.
(B) Osmosis: This is the phenomenon of solvent molecules moving across a semi-permeable membrane from a region of lower solute concentration to a region of higher solute concentration. It describes solvent movement, not the movement of colloidal particles themselves.
(C) Electrodialysis: This is a process used for the purification of colloidal solutions. It involves removing electrolytes (impurities) from a colloidal dispersion by applying an electric field across a compartment separated by semi-permeable membranes. It's a purification technique, not a fundamental type of movement of the colloidal particles.
(D) Electrophoresis: This is the phenomenon where charged colloidal particles move under the influence of an applied electric field. Positively charged colloidal particles migrate towards the cathode (negative electrode), and negatively charged colloidal particles migrate towards the anode (positive electrode). This movement is a direct consequence of the charge developed on the colloidal particles and is used to determine the charge on the particles or to separate them. Step 3: Conclude the correct term.
The movement of colloidal particles specifically "after developing charge" and under the influence of an electric field is precisely defined by Electrophoresis.