The optimum reaction conditions for the synthesis of polystyrene from styrene monomer to achieve the highest yield and highest molecular weight depend on the specific polymerization method being used. However, in general, the following conditions can be considered:1. Temperature: The optimal temperature for the synthesis of polystyrene is typically in the range of 60-120C. Higher temperatures can lead to faster reaction rates and higher molecular weights, but they can also cause side reactions and degradation of the polymer. Therefore, it is essential to find a balance between reaction rate and polymer stability.2. Initiator concentration: The concentration of the initiator plays a crucial role in determining the molecular weight and yield of the synthesized polystyrene. A higher initiator concentration leads to a higher number of polymer chains being formed, resulting in a lower molecular weight. On the other hand, a lower initiator concentration results in fewer polymer chains and a higher molecular weight. However, too low initiator concentration can lead to incomplete conversion of the monomer, reducing the overall yield. Therefore, an optimal initiator concentration should be chosen to balance the molecular weight and yield.For free-radical polymerization, a common method for synthesizing polystyrene, an initiator concentration of 0.1-1.0 mol% relative to the styrene monomer is typically used. The choice of initiator also plays a role in determining the optimal conditions, as different initiators have different decomposition temperatures and efficiencies.In conclusion, the optimum reaction conditions for the synthesis of polystyrene from styrene monomer depend on the specific polymerization method and initiator used. Generally, a temperature range of 60-120C and an initiator concentration of 0.1-1.0 mol% can be considered optimal for achieving the highest yield and highest molecular weight. However, it is essential to fine-tune these conditions based on the specific system being used.