Q.What do you mean by green chemistry? How will it help decrease environmental pollution?

Green chemistry is essentially about utilising a set of principles that reduce or eliminate the use and generation of hazardous substances in the design, manufacture and application of chemical products, by using existing knowledge and principles of chemistry and other sciences to reduce the adverse impact on the environment. In short, it means doing chemistry in a way that prevents pollution rather than treating/cleaning it up after it has occurred — often summarised as 'pollution prevention at the molecular level'.

How it decreases pollution:

• It redesigns reactions and processes to use safer, less toxic starting materials and solvents.
• It aims for reactions with the maximum atom economy, so fewer unwanted by-products/waste are generated.
• It uses catalysts, non-toxic reagents and renewable feedstocks where possible.

Illustrative examples given in the NCERT text:

1. Dry cleaning of clothes: Conventionally, tetrachloroethylene was widely used as a dry-cleaning solvent, contaminating groundwater and being a suspected carcinogen. Green chemistry replaces it with liquid CO2, using a suitable surfactant — CO2 is non-toxic and does not pollute groundwater. …

Define green chemistry as pollution prevention through safer chemical design, then support it with the two standard NCERT examples (CO2-based dry cleaning, H …

• Giving only a vague definition ('eco-friendly chemistry') without the specific examples the chapter gives.
• Confusing green chemistry (prevention through better process/product design) with waste treatment/pollution con …