A sample of red ink (a colloidal suspension) is prepared by mixing eosine dye, egg white, HCHO and water. The component which ensures stability of the ink sample is :
- (A)Egg white✓ Correct
- (B)HCHO
- (C)Water
- (D)Eosin dye
Answer: (A)
Solution
A colloid is kept from coagulating by a protective colloid that coats the dispersed particles. In this red ink the egg-white protein adsorbs onto the surface of the eosin dye particles and forms a protective layer that stops them aggregating, so it is the egg white that gives the sol its stability. The formaldehyde merely acts as a preservative, water is only the dispersion medium and the eosin dye is the dispersed phase.
JEE Main · 2020 · 04 Sep 2020 · Shift 2 · Single correct option