Vidaara.orgClass 11 · Chemistry
CodeVID-C11-14-T3-01
Assignment — Green Chemistry & Control
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Section A carries 1 mark each, Section B 2 marks, Section C 3 marks and Section D 5 marks.
- Give chemical reasoning where asked. Only final answers are given at the end — for full solutions, raise your doubts with your teacher.
Section A — Multiple Choice Questions
5 × 1 = 5 marks
1.
The preferred order of waste management is:
- A.burn, bury, forget
- B.reduce, reuse, recycle
- C.dump, drain, dilute
- D.import, store, sell
2.
Green chemistry is best described as:
- A.cleaning up waste after release
- B.preventing pollution by design
- C.using more chlorine
- D.ignoring by-products
3.
A reaction is 'greener' when its atom economy is:
- A.lower
- B.higher
- C.zero
- D.negative
4.
Hydrogen peroxide bleaching produces, on decomposition:
- A.water and oxygen
- B.chlorine and acid
- C.carbon dioxide and soot
- D.ozone and PAN
5.
Biogas produced from biodegradable waste is mainly:
- A.methane
- B.chlorine
- C.sulphur dioxide
- D.nitrogen
Section B — Short Answer (2 marks)
3 × 2 = 6 marks
6.
What is atom economy, and why does green chemistry value it?
7.
Give two reasons why liquid CO2 dry cleaning is greener than using PERC.
8.
State two strategies to control air pollution from industries.
Section C — Short Answer (3 marks)
2 × 3 = 6 marks
9.
Explain three principles or practices of green chemistry with an example of each.
10.
Describe how biodegradable and non-biodegradable wastes should be managed.
Section D — Long Answer (5 marks)
1 × 5 = 5 marks
11.
Explain the concept of green chemistry, the idea of atom economy, and discuss three real examples (H2O2 bleaching, solvent replacement, liquid-CO2 dry cleaning) that show how it reduces pollution.
Answer Key
Section A — Multiple Choice Questions
- (B) reduce, reuse, recycle
- (B) preventing pollution by design
- (B) higher
- (A) water and oxygen
- (A) methane
Section B — Short Answer (2 marks)
- Atom economy is the fraction of reactant atoms that end up in the desired product. Green chemistry values high atom economy because it means less waste is generated as by-products.
- Liquid CO2 is non-toxic and does not contaminate groundwater like the suspected carcinogen PERC, and it can be recovered and reused rather than released as hazardous waste.
- Scrub or remove pollutant gases (e.g. SO2) from flue gases before release, and switch to cleaner fuels or filters/electrostatic precipitators to trap particulates.
Section C — Short Answer (3 marks)
- Prevent waste at source (e.g. H2O2 bleaching instead of chlorine); use safer solvents (e.g. water or liquid CO2 instead of organic solvents); maximise atom economy so more reactant atoms become product, reducing by-products.
- Segregate the two. Biodegradable waste (food/plant matter) can be composted or digested to make biogas; non-biodegradable waste (plastic, glass, metal) should be recycled or safely disposed of, not dumped together.
Section D — Long Answer (5 marks)
- Green chemistry designs products and processes that reduce or eliminate hazardous substances, preventing pollution at source rather than cleaning it up. Atom economy is the fraction of reactant atoms that end up in the product; high atom economy means little waste. Examples: (1) bleaching with H2O2, which decomposes to water and oxygen, avoiding toxic organochlorines; (2) replacing volatile organic solvents with water or liquid CO2; (3) dry cleaning with reusable liquid CO2 instead of the carcinogen PERC. Together these cut hazardous waste, protect water and air, and support sustainable development.
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