Question

Green chemistry deals with:

Answer 1

Hint :Green chemistry is the approach in chemical sciences that efficiently uses renewable raw materials, eliminating waste and avoiding the use of toxic and hazardous reagents and solvents in the manufacture and application of chemical products. Green chemistry takes into account the environmental impact and seeks to prevent or lessen that impact.

Complete Step By Step Answer:
Green chemistry is defined as the application of a set of principles that help to reduce or eliminate the use or generation of hazardous substances in the design, manufacture, and application of chemical products. Given below are principles that demonstrate the breadth of the concept of green chemistry:
1. Prevent waste: Design chemical syntheses to prevent waste. Leave no waste to treat or clean up.
2. Maximize atom economy: Design syntheses so that the final product contains the maximum proportion of the starting materials. Waste few or no atoms.
3. Design less hazardous chemical syntheses: Design syntheses to use and generate substances with little or no toxicity to either humans or the environment.
4. Design safer chemicals and products: Design chemical products that are fully effective yet have little or no toxicity.
5. Use safer solvents and reaction conditions: That is avoid using solvents, separation agents, or other auxiliary chemicals. If you must use these chemicals, use safer ones.
6. Increase energy efficiency: Run chemical reactions at room temperature and pressure whenever possible.
7. Use renewable feedstocks: It includes use of starting materials , which is also known as feedstocks, that are renewable rather than depletable. The source of renewable feedstocks is often agricultural products or the wastes of other processes; the source of depletable feedstocks is often fossil fuels (petroleum, natural gas, or coal) or mining operations.
8. Avoid chemical derivatives: Avoid using blocking or protecting groups or any temporary modifications if possible. Derivatives use additional reagents and generate waste.
9. Use catalysts, not stoichiometric reagents: Minimize waste by using catalytic reactions. Catalysts are effective in small amounts and can carry out a single reaction many times. They are preferable to stoichiometric reagents, which are used in excess and carry out a reaction only once.
10. Design chemicals and products to degrade after use: Design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment.
11. Analyze in real time to prevent pollution: Include in-process, real-time monitoring and control during syntheses to minimize or eliminate the formation of byproducts.
12. Minimize the potential for accidents: Design chemicals and their physical forms (solid, liquid, or gas) to minimize the potential for chemical accidents including explosions, fires, and releases to the environment.
Hence, we may conclude that Green chemistry deals with reduced use of harmful hazardous substances.

Additional Information:
In the year 1998, Paul Anastas and John C.Warner published the set of principles to guide green chemistry. The set of twelve principles has given a range of ways to reduce the environmental and health effects of chemical productions. It also gives the scope for the research and development in green technology.

Note :
Students may relate the concept of green chemistry as environmental chemistry. However both these terms hold a different meaning. Green chemistry deals with the chemical reactions and chemical engineering of products and processes. While environmental chemistry focuses on the effect of pollutants on nature.