Question

The size of the colloidal particle lies in the range:
(A) $10nm - 1000m$
(B) $10nm - 1000nm$
(C) $1nm - 1000nm$
(D)${10^{ - 5}}cm - {10^{ - 7}}cm$

Answer 1

Hint: A colloid is typically a two phase system consisting of a continuous phase and dispersed phase. They are larger than simple molecules but are small enough to remain suspended.

Complete Step by step answer: Colloidal particles are larger than simple molecules but small enough to remain suspended. Their range of diameters is between ${10^{ - 5}}cm - {10^{ - 7}}cm$
A colloid is a heterogeneous system. That means, it is a mixture of more than one substance. In this system, usually, one substance is dispersed as very, fine particles in another substance. Let us say, the substance which is being dispersed as a fine particle is A. And the substance, in which it is being dispersed is B.
Then A is called the colloidal particle and B is called the dispersion medium. B is in solution form. The essential difference between a solution and a colloid is that of particle size. In a solution, B, the particles might be ions or small molecules. But in A, the particles might be a single macromolecule or it can be a mixture of different molecules.
Colloids can be larger particles compared to the particles present in the dispersed medium or solution. They are not too large to settle at the bottom of the solution. They remain suspended in the solution.

Therefore, from the above explanation the correct option is (D) ${10^{ - 5}}cm - {10^{ - 7}}cm.$

Note: The term colloid is important to be considered here. This is otherwise a factual question. But if you know what colloids mean, then you can compare all the options and observe that all the other options are given in terms of nanometers which is a very small unit. So you can predict that (D) should be the correct option.