Question

Size of colloidal particles may range from
A. ${\text{1 to 1000 nm}}$
B. ${\text{10 to 100 pm}}$
C. ${\text{1 to 100 pm}}$
D. ${\text{1 to 10 nm}}$

Answer 1

The particles in a colloid are larger than most simple molecules; however, colloidal particles are small enough that they do not settle out upon standing. This makes them small enough to be suspended in the fluid by thermal motion, provided the buoyancy mismatch between the particles and the fluid is not too large.

Complete answer:
Before we move forward with the solution of this given question, let us first understand some basic concepts about colloids:
Colloids: colloids can be defined as a mixture where one of the substances is split into very minute particles which are dispersed throughout a second substance. The minute particles are known as colloidal particles.
The colloid is a heterogeneous system in which one substance is dispersed as very fine particles in another substance called dispersion medium.
The most important difference between a solution and a colloid is that of particle size. While in a solution, the constituent particles are ions or small molecules, in a colloid, the dispersed phase may consist of particles of a single macromolecule (such as protein or synthetic polymer) or an aggregate of many atoms, ions or molecules.
Colloidal particles are larger than simple molecules but small enough to remain suspended. Their range of diameters is between 11 and 1000nm
The correct answer is option A.

Note:
Colloidal particles range in diameter from 1-1000 nanometers and can be solid, liquid, or gaseous. In other words, the colloidal solution is a heterogeneous dispersion of solute particles into the solvent. Particles are visible only with an ultra microscope.