Question

Colloidal particles dispersed in a liquid medium undergo a random, zigzag motion called the Brownian movement. The reason for this phenomenon is:

• A. Surface tension
• B. Extensive and uniform solvation
• C. Unbalanced forces caused by the bombardment of atoms of dispersion medium that surround the dispersed phase particles
• D. None of the above

Answer 1

The correct option is C Unbalanced forces caused by the bombardment of atoms of dispersion medium that surround the dispersed phase particles

Brownian movement arises from unbalanced collisions between the liquid molecules of the dispersion medium and the solid particles of the dispersed phase. In case of suspensions, the larger particles suspended in the medium experience collisions from different directions that cancel out overall. However, for particles of colloidal dimensions, the net force due to molecular collisions fluctuates randomly.
The other options are not accurate.