Which process results in complete separation of oil from water, forming a single continuous oil layer at the top?

• A. Creaming
• B. Flocculation
• C. Coalescence
• D. Breaking

Answer: (D)

Emulsions destabilize until the two liquids fully separate. The process that leads to complete separation with a single continuous oil layer at the top is breaking. When breaking occurs, the dispersed oil droplets merge (coalesce) until they form one continuous oil phase, which, because oil is less dense than water, rises to the top as a single layer. This is different from creaming, which only concentrates droplets at the surface without full coalescence; from flocculation, where droplets cluster but remain as individual droplets; and from coalescence alone, which can enlarge droplets without guaranteeing complete separation into two distinct phases.