An emulsion is defined as which of the following?

• A. A stable mixture of two or more liquids that are not normally soluble in each other
• B. A homogeneous mixture of two liquids
• C. A suspension of solid particles in a liquid
• D. A single phase liquid

Answer: (A)

An emulsion is a mixture in which one liquid is dispersed as tiny droplets within another liquid that normally does not mix with it. This creates a two-phase system rather than a single uniform phase. Emulsions stay together because an emulsifying agent lowers the interfacial tension between the liquids and stabilizes the droplets, preventing them from rapidly coalescing. That’s why oil-and-water mixtures can behave like emulsions when stabilized, such as in foods like mayonnaise or milk, where fat droplets are dispersed in water. The other descriptions don’t fit: a homogeneous liquid means both liquids have fully mixed into one phase, a suspension involves solid particles dispersed in a liquid, and a single-phase liquid has only one uniform phase with no dispersed droplets of a second liquid.