Question

How will you differentiate between a suspension and a colloid? Give one example of each.

Answer 1

Differences between a suspension and a colloid:

• If the solution is transparent or translucent to light, the mixture is a colloid and if the solution is opaque to light, it is a suspension.
• If the particles of the mixture are visible to the naked eye and settle down under the influence of gravity, it is a suspension, otherwise it is a colloid.

Colloid	Suspension
1. A colloid is a heterogeneous mixture in which the diameter of particles is ${10}^{-6}-{10}^{-9}\mathrm{m}$	1. A suspension is a heterogeneous mixture in which the diameter of the particles is $>{10}^{-6}\mathrm{m}$ (greater than ${10}^{-6}\mathrm{m}$)
2. The particles of colloids are not visible to the naked eyes but visible through a powerful microscope.	2. Particles are visible to the naked eyes due to the greater size.
3. Particles of colloids do not settle down under the influence of gravity when left undisturbed.	3. Particles of suspensions that remain suspended in the solvent settle down at the bottom of the container under the influence of gravity when left undisturbed.
4. All colloids scatter the beam of light passing through it and make the path of light visible called the Tyndall effect.	4. In general, suspensions do not show the Tyndall effect. However, it is observed in suspensions with fine sized particles.
5. Brownian movement i.e.; the random zig-zag movement of particles is observed in the solvent (dispersion medium).	5. In general, the Brownian movement is not shown by suspensions because of the large particle size. However, it is observed in suspensions with fine-sized particles.
6. Colloids are translucent to light i.e.; allow light to pass through them only partially.	6. Suspensions are opaque to light i.e.; they do not allow light to pass through them.
7. Examples: Milk, blood, soap solution etc.	7. Examples: Muddy water, mixture of limestone or Calcium carbonate $\left({\mathrm{CaCO}}_3\right)$ in Water $\left({\mathrm{H}}_2\mathrm{O}\right)$.