However, I can provide you with some general information and examples that you can include in your answers for the Chemistry optional subject. Please keep in mind that these examples are not exhaustive, and it's always a good idea to research and include relevant and recent case studies in your answers.

1. Case studies in Organic Chemistry:
- The discovery and synthesis of penicillin: This case study highlights the importance of organic chemistry in the development of antibiotics. You can discuss the structure, synthesis, and mechanism of action of penicillin, as well as its impact on healthcare and the treatment of bacterial infections.
- The synthesis of Taxol: Taxol is a potent anti-cancer drug derived from the bark of the Pacific yew tree. Its synthesis posed significant challenges due to its complex structure. You can discuss the various synthetic approaches that scientists developed to produce Taxol and the importance of organic chemistry in drug discovery.

2. Case studies in Inorganic Chemistry:
- The Haber-Bosch process: This case study focuses on the synthesis of ammonia from nitrogen and hydrogen gases. You can discuss the significance of the Haber-Bosch process in the production of fertilizers and its impact on agriculture and food production.
- Zeolites in catalysis: Zeolites are crystalline aluminosilicates with well-defined porous structures that are widely used as catalysts in various industrial processes. You can discuss the role of zeolites in catalysis and their applications in petrochemical and environmental industries.

3. Case studies in Physical Chemistry:
- The discovery of superconductivity: Superconductivity is a phenomenon in which certain materials exhibit zero electrical resistance at low temperatures. You can discuss the discovery of high-temperature superconductors and their potential applications in energy transmission and storage.
- The study of reaction kinetics: Reaction kinetics deals with the rates at which chemical reactions occur. You can discuss the study of reaction kinetics in understanding the mechanism of chemical reactions and optimizing reaction conditions for industrial processes.

Remember to provide detailed explanations, including relevant concepts, mechanisms, and applications of the case studies in your answers. Additionally, it's essential to ensure that your answers are well-structured and visually appealing by using appropriate headings and bullet points.