Question

What is Brownian movement and why is it exhibited by colloidal solutions?

Answer 1

Brownian movement is the continuous, random zig-zag motion of colloidal particles observed under an ultramicroscope. It occurs due to unequal bombardments by the rapidly moving molecules of the dispersion medium on the colloidal particles. This causes the particles to move erratically. Brownian movement is exhibited by colloidal solutions because their small particles are constantly hit by the molecules of the dispersion medium, preventing sedimentation and thus imparting stability to the colloid. As the particle size increases, it diminishes and becomes invisible in suspensions.