Green Chemistry: principles and metrics MCQs With Answer

Introduction: Green Chemistry: principles and metrics MCQs With Answer is designed to help M.Pharm students strengthen understanding of sustainable practices in pharmaceutical synthesis and process development. This short quiz collection emphasizes core green chemistry principles, quantitative metrics such as atom economy, E-factor, PMI and reaction mass efficiency, and practical choices like solvents, catalysts and renewable feedstocks. Questions are targeted at the level required for advanced organic chemistry coursework and industrial process optimization, promoting deeper comprehension of how to minimize waste, energy use and hazards while maintaining product quality. Use these MCQs to test knowledge, prepare for exams, or guide greener decision-making in drug research and manufacturing.

Q1. What is the primary aim of green chemistry?

• Design chemical products and processes that reduce or eliminate the use and generation of hazardous substances
• Maximize product yield only, irrespective of hazards
• Increase the number of synthetic steps to ensure robustness
• Delay regulatory compliance to later stages of development

Correct Answer: Design chemical products and processes that reduce or eliminate the use and generation of hazardous substances

Q2. How many foundational principles of green chemistry were articulated by Anastas and Warner?

• 12
• 10
• 8
• 15

Correct Answer: 12

Q3. Which expression correctly defines atom economy?

• Molecular weight of desired product divided by the sum of molecular weights of all reactants, multiplied by 100
• Mass of waste produced divided by mass of product
• Total mass of inputs including solvent divided by mass of product
• Mass of carbon in product divided by mass of carbon in reactants, multiplied by 100

Correct Answer: Molecular weight of desired product divided by the sum of molecular weights of all reactants, multiplied by 100

Q4. The E-factor is most accurately defined as:

• Total mass of waste generated divided by mass of product
• Molecular weight of product divided by molecular weight of reactants times 100
• Mass of desired product divided by total mass of reactants
• Mass of carbon incorporated into product divided by total carbon input

Correct Answer: Total mass of waste generated divided by mass of product

Q5. Which metric quantifies the total mass of all materials used per unit mass of product?

• Process Mass Intensity (PMI)
• Atom economy
• E-factor
• Carbon efficiency

Correct Answer: Process Mass Intensity (PMI)

Q6. Reaction Mass Efficiency (RME) is best expressed as:

• Mass of desired product divided by total mass of reactants, multiplied by 100
• Total mass of waste divided by mass of product
• Molecular weight of product divided by sum of molecular weights of reactants, multiplied by 100
• Mass of solvent used divided by mass of product

Correct Answer: Mass of desired product divided by total mass of reactants, multiplied by 100

Q7. Which metric explicitly includes solvents, reagents and auxiliaries when assessing material efficiency?

• Process Mass Intensity (PMI)
• Atom economy
• Carbon efficiency
• Yield percentage

Correct Answer: Process Mass Intensity (PMI)

Q8. Which green chemistry principle specifically recommends the use of catalytic reagents instead of stoichiometric reagents?

• Use catalytic reagents
• Prevention
• Design for degradation
• Reduce derivatives

Correct Answer: Use catalytic reagents

Q9. Which solvent choice is generally considered the greenest among these common options for many reactions?

• Water
• Benzene
• Dichloromethane
• Hexane

Correct Answer: Water

Q10. Which technique commonly reduces reaction time and energy consumption compared with conventional heating?

• Microwave-assisted heating
• Prolonged oil-bath reflux for many hours
• Maintaining sub-ambient temperatures for no reason
• Repeated freeze-thaw cycles

Correct Answer: Microwave-assisted heating

Q11. Carbon efficiency is defined as which of the following?

• Mass of carbon in the desired product divided by mass of carbon in all reactants, multiplied by 100
• Total mass of waste divided by mass of product
• Molecular weight of product divided by sum of molecular weights of reactants, multiplied by 100
• Mass of solvent used per mass of product

Correct Answer: Mass of carbon in the desired product divided by mass of carbon in all reactants, multiplied by 100

Q12. Which principle of green chemistry focuses on minimizing toxicity through molecular design?

• Design safer chemicals and products
• Maximize atom economy
• Use renewable feedstocks
• Increase energy input to drive reaction to completion

Correct Answer: Design safer chemicals and products

Q13. Which of the following is NOT commonly considered a green chemistry metric?

• Thiele modulus
• E-factor
• Atom economy
• Process Mass Intensity (PMI)

Correct Answer: Thiele modulus

Q14. Click chemistry is often cited as green because it typically provides:

• High yields, high selectivity and simple purification
• High energy consumption and many byproducts
• Extensive use of stoichiometric toxic reagents
• Multiple protection-deprotection steps

Correct Answer: High yields, high selectivity and simple purification

Q15. A Life Cycle Assessment (LCA) in green chemistry is used to:

• Evaluate environmental impacts across the entire life cycle of a product or process
• Measure only laboratory safety incidents
• Determine the single-step yield of a reaction
• Calculate the market price of a drug

Correct Answer: Evaluate environmental impacts across the entire life cycle of a product or process

Q16. Which is an example of a renewable feedstock suitable for green pharmaceutical processes?

• Glucose derived from biomass
• Crude oil
• Natural gas
• Coal tar

Correct Answer: Glucose derived from biomass

Q17. Which green chemistry principle encourages designing chemical products to break down into non‑hazardous substances after use?

• Design for degradation
• Atom economy
• Use of auxiliaries
• Increase reaction steps for selectivity

Correct Answer: Design for degradation

Q18. Which solvent selection guide is widely used in the pharmaceutical industry to rank solvents by health, safety and environmental criteria?

• GSK solvent selection guide
• OSHA solvent priority list
• IUPAC standard solvent ranking
• USP solvent monograph ranking

Correct Answer: GSK solvent selection guide

Q19. Which approach is most effective at reducing the E-factor in a synthetic process?

• Switch to catalytic, atom-economical routes and minimize solvent/auxiliary use
• Increase stoichiometric excesses of reagents to drive conversion
• Introduce multiple protection-deprotection sequences
• Replace catalysts with stoichiometric metal reagents

Correct Answer: Switch to catalytic, atom-economical routes and minimize solvent/auxiliary use

Q20. Which statement correctly contrasts atom economy and reaction yield?

• Atom economy describes how well reactant atoms are incorporated into the desired product and is independent of the experimental yield
• High atom economy always guarantees a high experimental yield
• Atom economy is identical to percent yield
• Reaction yield accounts for theoretical incorporation of atoms, but atom economy measures mass of waste

Correct Answer: Atom economy describes how well reactant atoms are incorporated into the desired product and is independent of the experimental yield

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