Question

The average size of the colloid is of the order of:
A. ${10^{ - 12}}m - {10^{ - 19}}m$
B. ${10^{ - 7}}m - {10^{ - 9}}m$
C. ${10^{ - 9}}m - {10^{ - 12}}m$
D. ${10^{ - 6}}m - {10^{ - 19}}m$

Answer 1

Hint:Colloids are the homogeneous substance (non-crystalline). They are consisting of large molecules or ultramicroscopic particles of one substance which are dispersed through a second substance. Gels, sols and emulsions are some examples of colloids.

Complete answer:
In simple words we can describe colloids as “a phase separated mixture is called colloid.” In colloids, one substance of microscopically dispersed insoluble or soluble particles is suspended throughout another substance. Sometimes the dispersed substance alone is called the colloid. In colloids there are two terms which are defined that are the dispersion medium and second one dispersion phase. The dispersed phase can be gas, solid or liquid. Similarly, dispersion mediums can be gas, liquid or solid. On the basis of the interaction between the particles of dispersion medium and dispersion phase there are two types of colloids.
These two types of colloids are:
1. Hydrophilic colloids
2. Hydrophobic colloids
In a colloid, if particles are attracted towards water then these colloids are called hydrophilic colloids.
And in a colloid, if particles are not attracted towards water then these colloids are called hydrophobic colloids.
The average size of the colloid is defined as the order of ${10^{ - 7}}m - {10^{ - 9}}m$ .

So, option B is correct.

Note:
Aggregation takes place in colloids due to the sum of the interaction forces between particles. If attractive forces (such as van der Waals forces) prevail over the repulsive ones (such as the electrostatic ones) particles aggregate in clusters.Stability of colloids are hindered by the aggregation of particles and sedimentation phenomena. There are two methods which are used to stabilize the colloidal solution against aggregation. These two methods are electronic stabilization and steric stabilization.