Which statement is true about green chemistry principles?

• A. All reaction yields must exceed 95%
• B. Starting materials must be derived from nonrenewable resources
• C. Designing processes to minimize waste and hazard
• D. Hazardous solvents are preferred for efficiency

Answer: (C)

Green chemistry is centered on reducing the environmental impact of chemical processes by planning steps that generate as little waste as possible and minimize hazards. Designing processes with waste prevention and hazard reduction in mind leads to safer, cleaner methods, better resource use, and often lower costs. This includes choosing safer solvents, improving energy efficiency, and using catalysts to boost efficiency while cutting waste.

The other statements don’t fit this approach: insisting every reaction must reach an extremely high yield ignores the trade-offs between yield, waste, and safety; many green processes accept good yields if they minimize waste and hazard. Requiring starting materials from nonrenewable resources goes against the move toward renewable resources and sustainability. Preferring hazardous solvents would increase risk and environmental harm, contrary to green chemistry goals.

So, designing processes to minimize waste and hazard is the true principle in this context.