Question

What would you observe when:

a colloidal solution of starch is passed through an ordinary filter paper?

Answer 1

Substances are classified into solution, colloids, and suspension depending upon the property of the particles present in it

True solution	Colloids	Suspension
Less than 1 nm sized particles dissolved in particular solvent	Particles of 1-1000 nm sized particles dispersed in the medium	Particles of size greater than 1000 nm size, suspended in the medium
Particles do not settle down on standing, and do not show Tyndall effect	Particles do not settle down on standing (can be forced to settle by centrifugation method) and show Tyndall effect	Particles settle down on standing
Example: sugar solution	Example: milk	Example: sand in water

One of the main property of the colloidal solution is Tyndall effect, i.e., when light passed through the colloidal solution, the path of the light become visible due to the scattering of light by the dispersed particles.

Starch is a colloidal solution, so the particles have size 1-1000 nm which can pass through the filter paper. Therefore, we can not use ordinary filter paper to separate the colloidal particles.