Green Chemistry MCQ Quiz - Objective Question with Answer for Green Chemistry - Download Free PDF

CONCEPT:

Green Chemistry in Nanoparticle Synthesis

• Green chemistry aims to design chemical products and processes that reduce or eliminate the use and generation of hazardous substances.
• It emphasizes the use of environmentally benign solvents, renewable feedstocks, and energy efficiency, among other principles.

EXPLANATION:

• Chemical vapor deposition (Option 1) often involves the use of toxic and hazardous gases.
• Sol-gel process (Option 2) can use organic solvents that may be harmful, although some variations use water-based systems.
• Biological methods (Option 3) utilize natural organisms like bacteria, fungi, and plants which act as eco-friendly factories for nanoparticle synthesis, minimizing the need for harmful solvents and reagents.
• Physical vapor deposition (Option 4) typically requires high energy input and may involve hazardous materials.
• Biological methods align best with green chemistry principles by using safe, renewable, and biodegradable resources.

Therefore, the method that primarily benefits from Green Chemistry principles in the synthesis of nanoparticles is option 3, Biological methods.

CONCEPT:

Green Chemistry and Solvent-Free Reactions

• Green chemistry emphasizes the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances.
• A key principle of green chemistry is to conduct reactions under solvent-free conditions whenever possible to minimize the environmental impact.

EXPLANATION:

• Supercritical carbon dioxide is specifically known for enabling reactions under solvent-free conditions.
• Supercritical carbon dioxide (scCO₂) is a state of carbon dioxide where it is held at or above its critical temperature and pressure, making it neither a liquid nor a gas but possessing properties of both.
• scCO₂ is an environmentally friendly solvent that can replace traditional organic solvents, reducing the release of volatile organic compounds (VOCs).
• Reactions conducted in scCO₂ often do not require additional solvents, thus aligning with the principles of green chemistry.

Therefore, the correct answer is option 1, supercritical carbon dioxide.

CONCEPT:

Key Challenges in Large-Scale Implementation of Green Synthesis

• Green Synthesis refers to environmentally friendly chemical processes and methodologies that minimize waste and reduce the use of hazardous substances.
• While Green Synthesis offers numerous benefits, its large-scale implementation faces several challenges.

EXPLANATION:

• Difficulty in minimizing waste by-product formation
• Minimizing waste by-product formation is a challenge, but advancements in process optimization and catalytic methods have provided solutions.
• Lack of understanding of the environmental impact of new materials
• Understanding the environmental impact of new materials is important, but it is not the primary challenge for large-scale implementation.
• High energy requirements for scaling up the processes
• High energy requirements for scaling up the processes is a challenge, but innovations in energy-efficient methods are being developed.
• Difficulty in sourcing renewable feedstocks
• is the key challenge because:
  • Renewable feedstocks are essential for sustainable Green Synthesis processes.
  • Consistent and reliable sourcing of renewable feedstocks can be difficult due to factors like seasonal availability, geographic limitations, and competition with food production.

Therefore, the key challenge in the large-scale implementation of Green Synthesis for industrial processes is the difficulty in sourcing renewable feedstocks.

CONCEPT:

Green Chemistry Principle: Designing Safer Chemicals

• Green Chemistry aims to design chemical products and processes that reduce or eliminate the use and generation of hazardous substances.
• The principle of "Designing Safer Chemicals" focuses on creating chemicals with minimal toxicity, posing less risk to human health and the environment.
• This principle emphasizes the need for chemicals that are effective and safe for use in both industrial and consumer applications, without causing harm to living organisms or ecosystems.

EXPLANATION:

•  "Creating chemicals with minimal toxicity that pose less risk to human health and the environment" is the correct answer. This aligns with the goal of Green Chemistry to ensure the safety of chemicals in their production, use, and disposal.
• While economic viability is important, Green Chemistry prioritizes environmental and health considerations over mere cost-effectiveness.
•  Reducing manufacturing costs at the expense of environmental impact goes against the core principles of Green Chemistry, which advocates for sustainability.
• The aesthetic properties of chemicals are not the primary focus in Green Chemistry, which aims to reduce environmental harm and toxicity, rather than enhancing appearance.

The correct answer is: A) Creating chemicals with minimal toxicity that pose less risk to human health and the environment.

Concept:

Green Reagents

• Green reagents are chemicals that are environmentally friendly, non-toxic, and sustainable for chemical reactions.
• They promote the principles of green chemistry, focusing on reducing hazardous substances and minimizing environmental impact.
• An example of a green reagent is hydrogen peroxide (H₂O₂), which is a clean oxidant as it decomposes into water and oxygen after the reaction.

Explanation:

• Hydrogen peroxide: It is a green reagent used as an oxidizing agent in many reactions because it is environmentally benign, producing only water and oxygen as byproducts.
• Benzene: Benzene is toxic and a known carcinogen, making it unsuitable as a green reagent.
• Carbon tetrachloride: This compound is highly toxic and ozone-depleting, which excludes it from being a green reagent.
• Methyl isocyanate: It is a hazardous chemical with severe toxic effects, making it incompatible with the principles of green chemistry.

Therefore, the correct answer is: Hydrogen peroxide.

Correct answer: 4)

Concept:

Principles of Green Chemistry:

• The use of starting materials, reagents and solvents which are less hazardous to man and his environment.
• More efficient use of raw materials.
• Utilisation of chemical reactions which completely incorporate the starting materials in to final products and last amount of by product.
• Search new alternatives which are environmental friendly.
• It is better to prevent the waste than to treat or cleanup the waste after it has been created

Explanation:

• Green chemistry is the different process and methods that helps in minimizing the effects of pollution and eliminating the hazardous substances.
• It takes care that no products adds to the environmental pollution.
• Using plastic cans for neatly storing substance will not come under green chemistry.
• Water in lakes and rivers have been polluted by the use of plastic materials.
• The plastic materials are non-biodegradable.
• Green chemistry includes processes which lead to minimal pollution and less harm to environment. 

Conclusion:

Thus, Using plastic cans for neatly storing substances will not come under green chemistry.

Additional Information 

Concept:

• The greenhouse effect is caused by certain gases in the atmosphere.
• During the day time, heat is trapped by the earth and at night time the absorbed heat will be released back into space.
• But a few gases like carbon dioxide, methane, ozone etc. act as umbrellas around the earth and they do not allow the heat to escape into space. Thus, the earth's temperature increases and this effect is known as the greenhouse effect.

Explanation:

• Solar cooker contains a glass sheet, outer black coating and a vessel.
• This glass sheet traps the sun's heat.
• It helps in increasing the cooker's temperature and helps in cooking the food.
• But after the work is finished the glass sheet acts as a shield and does not allow the heat to escape into the space.

Thus, the glass sheet causes the greenhouse effect similar to the greenhouse gases.

Concept:

Green Reagents

• Green reagents are chemicals that are environmentally friendly, non-toxic, and sustainable for chemical reactions.
• They promote the principles of green chemistry, focusing on reducing hazardous substances and minimizing environmental impact.
• An example of a green reagent is hydrogen peroxide (H₂O₂), which is a clean oxidant as it decomposes into water and oxygen after the reaction.

Explanation:

• Hydrogen peroxide: It is a green reagent used as an oxidizing agent in many reactions because it is environmentally benign, producing only water and oxygen as byproducts.
• Benzene: Benzene is toxic and a known carcinogen, making it unsuitable as a green reagent.
• Carbon tetrachloride: This compound is highly toxic and ozone-depleting, which excludes it from being a green reagent.
• Methyl isocyanate: It is a hazardous chemical with severe toxic effects, making it incompatible with the principles of green chemistry.

Therefore, the correct answer is: Hydrogen peroxide.

Concept:

Nanoparticles

• Nanoparticles are particles with at least one dimension in the nanometer scale.
• The unique properties of nanoparticles arise due to their small size and high surface area to volume ratio.
• They are widely used in various fields, including medicine, electronics, and materials science, due to their unique chemical, physical, and biological properties.

Explanation:

• 1-100 nanometers: This is the typical size range of nanoparticles. Below 100 nanometers, particles exhibit quantum effects and enhanced surface area.
• 100-1000 nanometers: This range corresponds to larger particles, often classified as sub-microparticles rather than nanoparticles.
• 1-10 micrometers: This range applies to microparticles, which are significantly larger than nanoparticles.
• 10-100 micrometers: This range applies to macro-sized particles, which do not exhibit nanoparticle-specific properties.

Therefore, the correct answer is: 1-100 nanometers.

Concept:

• The greenhouse effect is caused by certain gases in the atmosphere.
• During the day time, heat is trapped by the earth and at night time the absorbed heat will be released back into space.
• But a few gases like carbon dioxide, methane, ozone etc. act as umbrellas around the earth and they do not allow the heat to escape into space. Thus, the earth's temperature increases and this effect is known as the greenhouse effect.

Explanation:

• Solar cooker contains a glass sheet, outer black coating and a vessel.
• This glass sheet traps the sun's heat.
• It helps in increasing the cooker's temperature and helps in cooking the food.
• But after the work is finished the glass sheet acts as a shield and does not allow the heat to escape into the space.

Thus, the glass sheet causes the greenhouse effect similar to the greenhouse gases.

CONCEPT:

Green Chemistry in Nanoparticle Synthesis

• Green chemistry aims to design chemical products and processes that reduce or eliminate the use and generation of hazardous substances.
• It emphasizes the use of environmentally benign solvents, renewable feedstocks, and energy efficiency, among other principles.

EXPLANATION:

• Chemical vapor deposition (Option 1) often involves the use of toxic and hazardous gases.
• Sol-gel process (Option 2) can use organic solvents that may be harmful, although some variations use water-based systems.
• Biological methods (Option 3) utilize natural organisms like bacteria, fungi, and plants which act as eco-friendly factories for nanoparticle synthesis, minimizing the need for harmful solvents and reagents.
• Physical vapor deposition (Option 4) typically requires high energy input and may involve hazardous materials.
• Biological methods align best with green chemistry principles by using safe, renewable, and biodegradable resources.

Therefore, the method that primarily benefits from Green Chemistry principles in the synthesis of nanoparticles is option 3, Biological methods.

CONCEPT:

Green Chemistry and Solvent-Free Reactions

• Green chemistry emphasizes the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances.
• A key principle of green chemistry is to conduct reactions under solvent-free conditions whenever possible to minimize the environmental impact.

EXPLANATION:

• Supercritical carbon dioxide is specifically known for enabling reactions under solvent-free conditions.
• Supercritical carbon dioxide (scCO₂) is a state of carbon dioxide where it is held at or above its critical temperature and pressure, making it neither a liquid nor a gas but possessing properties of both.
• scCO₂ is an environmentally friendly solvent that can replace traditional organic solvents, reducing the release of volatile organic compounds (VOCs).
• Reactions conducted in scCO₂ often do not require additional solvents, thus aligning with the principles of green chemistry.

Therefore, the correct answer is option 1, supercritical carbon dioxide.

CONCEPT:

Key Challenges in Large-Scale Implementation of Green Synthesis

• Green Synthesis refers to environmentally friendly chemical processes and methodologies that minimize waste and reduce the use of hazardous substances.
• While Green Synthesis offers numerous benefits, its large-scale implementation faces several challenges.

EXPLANATION:

• Difficulty in minimizing waste by-product formation
• Minimizing waste by-product formation is a challenge, but advancements in process optimization and catalytic methods have provided solutions.
• Lack of understanding of the environmental impact of new materials
• Understanding the environmental impact of new materials is important, but it is not the primary challenge for large-scale implementation.
• High energy requirements for scaling up the processes
• High energy requirements for scaling up the processes is a challenge, but innovations in energy-efficient methods are being developed.
• Difficulty in sourcing renewable feedstocks
• is the key challenge because:
  • Renewable feedstocks are essential for sustainable Green Synthesis processes.
  • Consistent and reliable sourcing of renewable feedstocks can be difficult due to factors like seasonal availability, geographic limitations, and competition with food production.

Therefore, the key challenge in the large-scale implementation of Green Synthesis for industrial processes is the difficulty in sourcing renewable feedstocks.

CONCEPT:

Green Chemistry Principle: Designing Safer Chemicals

• Green Chemistry aims to design chemical products and processes that reduce or eliminate the use and generation of hazardous substances.
• The principle of "Designing Safer Chemicals" focuses on creating chemicals with minimal toxicity, posing less risk to human health and the environment.
• This principle emphasizes the need for chemicals that are effective and safe for use in both industrial and consumer applications, without causing harm to living organisms or ecosystems.

EXPLANATION:

•  "Creating chemicals with minimal toxicity that pose less risk to human health and the environment" is the correct answer. This aligns with the goal of Green Chemistry to ensure the safety of chemicals in their production, use, and disposal.
• While economic viability is important, Green Chemistry prioritizes environmental and health considerations over mere cost-effectiveness.
•  Reducing manufacturing costs at the expense of environmental impact goes against the core principles of Green Chemistry, which advocates for sustainability.
• The aesthetic properties of chemicals are not the primary focus in Green Chemistry, which aims to reduce environmental harm and toxicity, rather than enhancing appearance.

The correct answer is: A) Creating chemicals with minimal toxicity that pose less risk to human health and the environment.

Concept:

Sustainable Development

• Sustainable development refers to a development approach that balances economic growth, social inclusion, and environmental protection to ensure long-term benefits.
• The widely accepted definition of sustainable development comes from the Brundtland Report (1987): "Meeting the needs of the present without compromising the ability of future generations to meet their own needs."
• Key principles include intergenerational equity, resource efficiency, and environmental stewardship.

Explanation:

• Meeting the needs of the present without compromising the ability of future generations: This is the core principle of sustainable development, focusing on responsible resource use and long-term sustainability.
• Maximizing economic growth at all costs: This approach ignores environmental and social considerations, contradicting the principles of sustainability.
• Exploiting natural resources for immediate benefits: This leads to resource depletion and environmental degradation, which are against the goals of sustainable development.
• Prioritizing industrial development over environmental concerns: This strategy neglects the balance required between economic and environmental needs.

Therefore, the correct answer is: Meeting the needs of the present without compromising the ability of future generations to meet their own needs.