Industrial Waste and Green Chemistry - UNSOLVED PRACTICE SET

Q7. State the 12 principles of green chemistry (list any six). Why is atom economy considered a key metric?

Q8. Calculate the atom economy for the synthesis of ibuprofen by the traditional method vs. the green BHC process. Why is the BHC process considered greener?

Q9. What is a supercritical fluid? Why is supercritical CO₂ considered a green solvent for extraction processes

Q10. Differentiate between "end-of-pipe" treatment and "green chemistry" approaches to pollution control.

Q11. Your school chemistry lab is being redesigned to be more environmentally friendly. Suggest three changes based on green chemistry principles.

Q12. Why is the use of biocatalysts (enzymes) preferred over chemical catalysts in green chemistry?

Q13. Discuss the 12 principles of green chemistry in detail:

(a) Prevention, atom economy, less hazardous chemical syntheses

(b) Designing safer chemicals, safer solvents and auxiliaries

(c) Design for energy efficiency, use of renewable feedstocks

(d) Reduction of derivatives, catalysis, design for degradation

(e) Real-time analysis for pollution prevention, inherently safer chemistry

Illustrate each principle with a relevant example from industry or research.

Q14. Explain green chemistry applications in Indian industry:

(a) The BHC process for ibuprofen synthesis — how atom economy improved from 40% to 77%

(b) Use of supercritical CO₂ in spice extraction in Kerala and Karnataka

(c) Biocatalysis in Indian pharmaceutical manufacturing (API synthesis)

(d) Green solvents (ionic liquids, water) replacing toxic organic solvents

(e) The concept of industrial symbiosis — how waste from one industry becomes feedstock for another (example: Tata Steel's slag utilisation)

Q15. India faces the challenge of balancing industrial growth with environmental protection. Discuss:

(a) Why India needs green chemistry more than developed countries (pollution burden, resource constraints)

(b) The role of CSIR labs and IITs in developing green technologies for Indian conditions

(c) Government initiatives: National Action Plan on Climate Change, Plastic Waste Management Rules, E-waste Rules

(d) How students can contribute to green chemistry — citizen science, awareness, sustainable lifestyle choices

Q16. The traditional synthesis of adipic acid (for nylon) uses benzene and produces N₂O as a by-product:

C₆H₆ → C₆H₁₂O₄ → HOOC(CH₂)₄COOH (with N₂O emission)

The green synthesis uses glucose and biocatalysis:

C₆H₁₂O₆ → HOOC(CH₂)₄COOH (no N₂O)

(a) Calculate the atom economy for both routes if the traditional route has a total reactant mass of 200 g producing 146 g adipic acid, while the green route uses 180 g glucose to produce 146 g adipic acid.

(b) If N₂O has a global warming potential 298 times that of CO₂, and the traditional process emits 0.3 kg N₂O per kg adipic acid, calculate the CO₂-equivalent emissions avoided per tonne of adipic acid by the green process.

(c) If India produces 100,000 tonnes of adipic acid annually, calculate the annual CO₂-equivalent savings if the green process is adopted.

Q17. A pharmaceutical company in Hyderabad synthesises a drug using two routes:

Route A (Traditional): Reactant mass = 500 kg, Product mass = 120 kg, Waste mass = 380 kg

Route B (Green): Reactant mass = 200 kg, Product mass = 120 kg, Waste mass = 80 kg

(a) Calculate the atom economy, E-factor, and percentage yield for each route.

(b) Calculate the cost savings if waste disposal costs ₹ 10,000 per tonne and raw materials cost ₹ 500 per kg.

(c) If the company produces 10 tonnes of drug annually, calculate the total annual savings by switching to Route B.

Q18. India's chemical industry generates 15 million tonnes of hazardous waste annually. Only 60% is treated, and the rest is dumped.

(a) Calculate the mass of untreated hazardous waste dumped annually.

(b) If green chemistry practices can reduce waste generation by 40%, calculate the new total waste and the reduction achieved.

(c) If implementing green chemistry costs ₹ 5000 crore but saves ₹ 8000 crore in treatment and liability costs over 10 years, calculate the net benefit and return on investment.