Question

Which below describes a way that emulsifying agents work?
I. Act as a monomolecular film to decrease interfacial tension.
II. Works by using repulsive electric forces.
III. Acts by forming a mechanical barrier between two immiscible liquids.
a. I only
b. II only
c. I and II
d. All of the above

Answer 1

d. All of the above.

All three are correct mechanisms by which emulsifying agents stabilize emulsions:
- I: Surfactants form a monomolecular film at the interface and lower interfacial tension, making droplet formation and stability easier.
- II: Ionic emulsifiers impart surface charge to droplets, producing electrostatic (repulsive) forces that prevent coalescence.
- III: Some emulsifiers (proteins, polymers, or solid particles — e.g., Pickering emulsions) form a mechanical/steric barrier around droplets that blocks coalescence.