The correct option for the question regarding the common method for synthesizing synthetic polymers through the process of adding monomers with unsaturated bonds is **B. Addition polymerization**. ### Detailed Explanation **1. Understanding Addition Polymerization:** Addition polymerization is a type of polymerization where monomers with unsaturated bonds (typically double bonds, such as alkenes) react to form a polymer. In this process, the double bonds in the monomers open up, allowing them to link together into long chains. This method is widely used in the production of many common synthetic polymers, such as polyethylene, polystyrene, and polyvinyl chloride (PVC). **2. Mechanism of Addition Polymerization:** The addition polymerization process generally involves three main steps: - **Initiation:** A free radical initiator (or heat, light, or other energy sources) generates free radicals that can react with the monomer to start the chain reaction. - **Propagation:** The free radical reacts with a monomer, creating a new radical that can react with another monomer, continuing the chain growth. - **Termination:** The reaction can terminate when two free radicals combine or when a radical reacts with a molecule that does not propagate the chain. **3. Why Other Options Are Incorrect:** - **A. Condensation Polymerization:** This method involves the reaction of monomers with functional groups (like -OH, -COOH, -NH2) that leads to the elimination of small molecules (like water or methanol) as byproducts. It does not primarily involve unsaturated bonds and is used for polymers like polyesters and polyamides. - **C. Copolymerization:** This is a specific type of polymerization where two different types of monomers are used to create a copolymer. While it can involve addition polymerization, it is not a method in itself but rather a variation of polymerization that can include both addition and condensation processes. - **D. Chain-growth Polymerization:** This term is often used interchangeably with addition polymerization, but it is broader and can include other mechanisms such as living polymerization. However, the question specifically asks for a method that involves unsaturated bonds, which is more accurately described by addition polymerization. ### Example Calculation: While there are no calculations directly involved in identifying the type of polymerization, understanding the molecular weight of the resulting polymer can be useful. For example, if you start with 100 grams of a monomer with a molecular weight of 100 g/mol, and you assume complete conversion with no side reactions, the number of moles of monomer used would be: \[ \text{Moles of monomer} = \frac{\text{mass}}{\text{molecular weight}} = \frac{100 \text{ g}}{100 \text{ g/mol}} = 1 \text{ mol} \] If the degree of polymerization (number of monomer units in the polymer) is 1000, the molecular weight of the polymer would be: \[ \text{Molecular weight of polymer} = \text{degree of polymerization} \times \text{molecular weight of monomer} = 1000 \times 100 \text{ g/mol} = 100,000 \text{ g/mol} \] ### Common Pitfalls: - Confusing addition polymerization with condensation polymerization due to their similar names. - Misunderstanding the role of unsaturated bonds in the polymerization process. - Overlooking the fact that not all polymerization processes involve the elimination of small molecules. ### Revision Summary: - **Addition polymerization** involves the reaction of unsaturated monomers to form polymers without the loss of small molecules. - **Condensation polymerization** produces polymers with the elimination of small byproducts and involves functional groups rather than unsaturated bonds. - **Copolymers** are made from two different monomers but can involve various polymerization methods. - **Chain-growth polymerization** is a broader term that includes addition polymerization but is not limited to it. By understanding these concepts, you can better grasp the different methods of polymer synthesis and their applications in chemistry.