Real-World Applications of Groups 16-18 Concepts

1. H2SO4 Manufacturing (Contact Process)

• H2SO4 is the most produced industrial chemical worldwide (>200 million tonnes/year)
• Used in: fertilizers (superphosphate of lime), detergents, dyes, explosives (TNT, picric acid), paints
• The Contact process replaced the older Lead Chamber process because it produces more concentrated acid

2. Bleaching Powder (CaOCl2) Applications $\text{Ca(OH)}_2 + \text{Cl}_2 \rightarrow \text{CaOCl}_2 + \text{H}_2\text{O}$

• Bleaching of cotton, linen, paper pulp (industrial bleaching)
• Water disinfection and purification
• Germicide and disinfectant in hospitals

3. HF in Industry $4\text{HF} + \text{SiO}_2 \rightarrow \text{SiF}_4 + 2\text{H}_2\text{O}$

• Glass etching: HF is the ONLY acid that attacks glass (SiO2). All other HX don't react with glass.
• Stored in plastic (PTFE/polyethylene) or lead containers — not glass

4. Ozone in Environmental Science

• Stratospheric ozone layer (15-35 km altitude) absorbs UV-B/UV-C
• Ozone depletion by CFCs (Freons): Cl radicals catalyze O3 → O2
• Industrial use: water purification, sterilization (stronger oxidant than Cl2)

5. Noble Gas Applications

• Xe in high-intensity lamps and ion thrusters (NASA)
• Clathrates of noble gases in inclusion compounds for drug delivery research
• Xenon anesthesia (expensive but used in critical care)

6. Interhalogen Compounds

• ClF3 used in uranium processing (converts UO2 to volatile UF6)
• ClF as a fluorinating agent in organic synthesis