____ is coalescence and creaming combined, where the oil separates completely from the water so that it floats at the top in a single, continuous layer.

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

Answer: (D)

This item tests how emulsions fail when destabilizing processes act together. Creaming is the up-and-down migration of droplets due to density differences, so you see a change in the distribution but the system can still be re-emulsified. Coalescence is when droplets fuse into larger droplets, increasing their size within the dispersed phase. When both processes occur to the extent that the oil completely separates from the water and forms a single, continuous oil layer at the top, the emulsion has broken. The oil layer sits atop the water because oil is less dense, and the continuous layer indicates full phase separation rather than just partial destabilization.