Which statement describes what happens to emulsions when left undisturbed?

Which statement describes what happens to emulsions when left undisturbed?

• A. They crystallize.
• B. They dissolve completely.
• C. They may separate unless continuously mixed.
• D. They become more stable.

Answer: (C)

Emulsions are mixtures where droplets of one liquid sit in another immiscible liquid. They are not perfectly stable and tend to reduce interfacial area and energy over time. When an emulsion is left alone, the droplets gradually collide and merge (coalesce), and the denser liquid tends to separate from the lighter one under gravity. This process leads to the dispersed phase rising or settling and a distinct separation into two layers. That tendency to separate unless some mixing or stabilization keeps the droplets dispersed is exactly what the statement describes. The other possibilities don’t fit this natural behavior. Crystallization implies solidifying components, which isn’t the typical fate of an emulsion. Complete dissolution would require the liquids to be miscible, which defeats the whole concept of an emulsion. Becoming more stable would require active stabilization; without disturbance or stabilizers, stability generally decreases over time.

Emulsions are mixtures where droplets of one liquid sit in another immiscible liquid. They are not perfectly stable and tend to reduce interfacial area and energy over time. When an emulsion is left alone, the droplets gradually collide and merge (coalesce), and the denser liquid tends to separate from the lighter one under gravity. This process leads to the dispersed phase rising or settling and a distinct separation into two layers. That tendency to separate unless some mixing or stabilization keeps the droplets dispersed is exactly what the statement describes.

The other possibilities don’t fit this natural behavior. Crystallization implies solidifying components, which isn’t the typical fate of an emulsion. Complete dissolution would require the liquids to be miscible, which defeats the whole concept of an emulsion. Becoming more stable would require active stabilization; without disturbance or stabilizers, stability generally decreases over time.