Question

A sample of red ink (a colloidal suspension) is prepared by mixing eosin dye, egg white, $\mathrm{HCHO}$ and water. The component which ensures the stability of the ink sample is?

• A. $\mathrm{HCHO}$
• B. Water
• C. Eosin dye
• D. Egg white

Answer 1

The correct option is D

Egg white

Explanation for the correct option:

(D)

1. Colloidal solution - Colloidal solution is a mixture in which highly tiny particles are suspended in a liquid substance in which it is insoluble and does not settle down at the bottom of the solution. Suspended particles are known as the dispersed phase and the liquid substance is known as the dispersion medium. The red ink is a colloidal solution.
2. Two types of colloidal sols are there- Lyophobic sols (liquid hating) - In such colloidal sols very little interaction is there between the dispersed phase and the dispersion medium. Lyophilic sols (liquid loving) - In such colloidal sols there is a high affinity between the dispersed phase and the dispersion medium.
3. The albumin present in egg white forms a lyophilic sol when we mix it with cold water. The presence of lyophilic sol brings stability. The lyophilic sol formed by egg albumin is stable and does not contain any type of impurities.
4. So, egg white ensures the stability of the ink sample (colloidal suspension) as it has albumin (lyophilic sol).
5. Water, eosin dye and $\mathrm{HCHO}$ do not have any such property of stabilizing colloid solutions to make the sample stable.

(A) The above detailed explanation shows that option (A) is incorrect.

(B) The above detailed explanation shows that option (B) is incorrect.

(C) The above detailed explanation shows that option (C) is incorrect.

Hence, option D is the correct answer.