MHT-CET Chemistry · Green Chemistry and Nanochemistry
Green Chemistry: the Principles, Atom Economy and Safer Solvents
Green chemistry designs processes that make less waste: its twelve principles favour prevention over clean-up, high atom economy, renewable feedstocks, fewer derivatives and safer solvents such as water and supercritical CO₂.
Why this matters
19 PYQs, mostly EASY. Eight name or misstate a principle, six are atom-economy arithmetic, and five pick a green solvent or a plant source. Three cards; the only one with a calculation is atom economy.
Concept 1 of 3: The Principles of Green Chemistry
Definition
- Prevention of waste; atom economy; less hazardous synthesis; safer chemicals; safer solvents and auxiliaries (minimum use); energy efficiency.
- Renewable feedstocks — chemicals from plants rather than crude oil.
- Reduce derivatives — avoid protection and deprotection steps.
- Catalysis; design for degradation (biodegradable pesticides); real-time analysis; safer chemistry for accident prevention.
- Examples: bio-plastics and bio-diesel; Draths and Frost made adipic acid from glucose with enzymes instead of from benzene.
| Statement | Verdict |
|---|---|
| Maximum use of auxiliary substances | Not a principleQ |
| Protection and deprotection is good practice | Not true — reduce derivativesQ |
| Good atom economy = few reactant atoms in the product | Not true — it means mostQ |
| Plant-based chemicals | Use of renewable feedstocksQ |
| Avoid protecting a group | Reduce derivativesQ |
| Adipic acid by enzymes (Draths and Frost) | From glucoseQ |
Practice this conceptself-check · 1 quick reps
The same idea in a real exam question:
Example 1 · Green Chemistry and Nanochemistry · Green Chemistry, Principles, Atom Economy and Green Solvents
Blaming two gases when one explains everything
Concept 2 of 3: Percentage Atom Economy
Definition
- % atom economy = (formula mass of desired product ÷ sum of formula masses of all reactants) × 100.
- Addition (C₂H₄ + H₂ → C₂H₆): 100% — the best. Substitution and esterification lose a small molecule.
- Rearranged: product mass = atom economy × reactant mass. 274 u at 50% → 137 u.
Atom economy
Worked example
Practice this conceptself-check · 2 quick reps
The same idea in a real exam question:
Example 2 · Green Chemistry and Nanochemistry · Green Chemistry, Principles, Atom Economy and Green Solvents
Leaving a reactant out of the sum
Concept 3 of 3: Green Solvents and Plant-Derived Compounds
Definition
- Green solvents: water, supercritical CO₂, ionic liquids. Avoid CH₂Cl₂, CHCl₃, CCl₄.
- Clove — eugenol: analgesic and antimicrobial.
- Turmeric — curcumin: the paper keys antiseptic.
Practice this conceptself-check
The same idea in a real exam question:
Example 3 · Green Chemistry and Nanochemistry · Green Chemistry, Principles, Atom Economy and Green Solvents
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Formulas (1)
- Percentage Atom Economy
Atom economy
Reference tables (2)
The Principles of Green Chemistry6 rows
| Statement | Verdict |
|---|---|
| Maximum use of auxiliary substances | Not a principleQ |
| Protection and deprotection is good practice | Not true — reduce derivativesQ |
| Good atom economy = few reactant atoms in the product | Not true — it means mostQ |
| Plant-based chemicals | Use of renewable feedstocksQ |
| Avoid protecting a group | Reduce derivativesQ |
| Adipic acid by enzymes (Draths and Frost) | From glucoseQ |
Watch out for (2)
- Blaming two gases when one explains everything→ The Principles of Green Chemistry
- Leaving a reactant out of the sum→ Percentage Atom Economy
Test yourself on Green Chemistry and Nanochemistry
15 past MHT-CET questions from this chapter, timed at 14 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.