What effect does a coalescing medium have on oil globules?

• A. Smaller
• B. Larger
• C. Denser
• D. More Stable

Answer: (B)

A coalescing medium encourages oil droplets to merge when they come into contact, so the oil globules become larger. In this setup, droplets collide and fuse, reducing the total interfacial area and releasing surface energy as they form a single bigger drop. As a result, the dispersed phase shifts from many small droplets to fewer, larger ones, which also helps with separation because larger droplets rise more quickly due to buoyancy.

Smaller droplets would imply ongoing breakup or strong stabilization, which isn’t the effect here. Density stays a property of the oil and water, not the droplet size. And while some emulsions are stabilized to resist coalescence, the defining outcome of introducing a coalescing medium is increased droplet size, not increased stability.