_____ can prevent caking.

• A. Sedimentation
• B. Creaming
• C. Flocculation
• D. Rupture

Answer: (C)

Flocculation prevents caking by creating loose, open aggregates (flocs) of particles that settle as a fluffy, porous sediment rather than packing into a dense, hard cake. When particles are flocculated, their interparticle forces are strong enough to bring them together but not so strong that the sediment becomes highly consolidated. The resulting bed has lots of voids and can hold water and air, making it easy to redisperse with gentle agitation. If a suspension is deflocculated, the particles settle slowly and the sediment can become a compact, irreversible cake upon consolidation, which is why caking is more of a problem. Sedimentation simply describes settling, and without flocculation that can still lead to a hard cake after compaction. Creaming involves droplets rising in emulsions, not powder caking, and rupture refers to breaking emulsions or films, not preventing caking.