The addition of a catalyst in the synthesis of polystyrene from styrene monomer via free radical polymerization can have a significant impact on both the yield and molecular weight of the resulting polymer.1. Yield: The use of a catalyst can increase the yield of polystyrene by accelerating the rate of the polymerization reaction. Catalysts lower the activation energy required for the reaction to occur, allowing more monomers to react and form polymer chains. As a result, the overall yield of polystyrene can be improved.2. Molecular weight: The effect of a catalyst on the molecular weight of polystyrene depends on the type of catalyst used and the reaction conditions. In general, catalysts can influence the molecular weight by affecting the initiation, propagation, and termination steps of the polymerization process.- Initiation: Catalysts can increase the rate of initiation by generating more free radicals, which can lead to a higher number of polymer chains being formed. This can result in a decrease in the average molecular weight of the polystyrene, as there are more chains with fewer monomer units.- Propagation: Some catalysts can also affect the propagation step by increasing the rate at which monomers are added to the growing polymer chains. This can lead to an increase in the molecular weight of the polystyrene, as the chains grow more quickly.- Termination: Catalysts can influence the termination step by promoting chain transfer reactions or increasing the rate of termination reactions. This can result in a decrease in the molecular weight of the polystyrene, as the polymer chains are terminated before they can grow to a larger size.Overall, the addition of a catalyst can have both positive and negative effects on the yield and molecular weight of polystyrene synthesized from styrene monomer via free radical polymerization. The specific impact will depend on the type of catalyst used and the reaction conditions, so it is essential to carefully select and optimize these factors to achieve the desired properties in the final polymer product.