Which process is described by oil droplets merging to form larger droplets and potentially leading to phase separation?

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

Answer: (C)

Coalescence is the process where oil droplets collide and fuse to form a larger droplet, which reduces the total number of droplets and can drive the dispersed phase to separate from the continuous phase as the oil-rich phase grows. This happens when the protective film at the oil–water interface becomes unstable or too thin to keep droplets apart, allowing fusion to occur. Creaming, on the other hand, is the movement of droplets due to density differences without changing their size; flocculation is droplets sticking together into clusters without merging into one larger droplet; breaking refers to droplets being torn apart by stress.