What is polymerization?

• A. Process of building large compounds by joining smaller ones
• B. The breaking down of polymers
• C. The separation of ions in solution
• D. The mixing of two immiscible liquids

Answer: (A)

Polymerization is the process of building large compounds by joining smaller units called monomers. When monomers link together, they form polymers—long chains or networks with repeating units that give the material new properties compared to the individual monomers. For example, many ethylene molecules join to make polyethylene.

There are common forms, such as addition polymerization, where monomers add together without releasing small molecules, and condensation polymerization, where a small molecule (often water) is released as bonds form. This idea of assembling big molecules from smaller building blocks is what this term describes.

Other processes described by the distractors involve different chemical changes: breaking down polymers is depolymerization, separation of ions in solution is dissociation or ionization, and mixing two immiscible liquids is a phase separation or emulsification process.