Question

State whether the statement is true of false
Statement: Milk is pure substance.
A. True
B. False

Answer 1

On the basis of the physical appearance of the colloidal solution, the type of dispersion medium can be identified. The physical appearance of milk is liquid, so the dispersion medium in milk is liquid that is water.

Step by step answer: A colloid is a mixture in which a phase remains dispersed in the suspension. The size of colloidal particles varies from $1$ to ${\text{1000 nm}}$. Due to the large size colloid solution contains the different phases of suspended particle and suspension medium. Colloids are heterogeneous mixtures, not pure solutions.

The colloidal solution is of $8$ types.
-Solid in gas. The colloidal type is an aerosol.
-Solid in liquid. The colloidal type is a sol.
-Solid in solid. The colloidal type is a solid-sol.
-Liquid in solid. The colloidal type is a gel.
-Liquid in liquid. The colloidal type is an emulsion.
-Liquid in gas. The colloidal type is a liquid aerosol.
-Gas in solid. The colloidal type is solid foam.
-Gas in liquid. The colloidal type is a foam.

Milk is an emulsion type colloid solution. In milk fat globules remain dispersed in water. So, milk is not a pure substance. It is a heterogeneous mixture.

Therefore, option (B) false, is correct.

Note: Milk is an example of colloid. The dispersed phase is fat globules which remain suspended in dispersion medium water. One must have a clear understanding of dispersed phase and dispersion medium to understand the concept of emulsion.