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Overview of Green Chemistry and Nanochemistry

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Estimated time: 33 minutes
Maharashtra State Board: Class 12

Definition: Green Chemistry

The use of chemistry for pollution prevention through environmentally conscious design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances is called green chemistry.

Maharashtra State Board: Class 12

Definition: Sustainable Development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs is called sustainable development.

Maharashtra State Board: Class 12

Key Points: Principles of Green Chemistry

No. Principle Main Idea Key Objective Example / Focus
1 Prevention of Waste Avoid formation of waste instead of treating it later Minimize waste generation Zero Waste Technology (ZWT)
2 Atom Economy Maximize incorporation of reactant atoms into final product Reduce by-products Higher % atom economy
3 Less Hazardous Chemical Synthesis Use safer reaction pathways Reduce toxic waste Replace harmful chemicals like DDT
4 Designing Safer Chemicals Design products with minimum toxicity Protect human health Develop low-toxicity chemicals
5 Use of Safer Solvents and Auxiliaries Use safer solvents and minimize auxiliary substances Reduce environmental impact Use water or supercritical CO₂
6 Design for Energy Efficiency Minimize energy requirements Reduce energy consumption Reactions at room temperature and pressure
7 Use of Renewable Feedstocks Prefer renewable raw materials Conserve non-renewable resources Plant-based raw materials
8 Reduce Derivatives Avoid unnecessary protection/deprotection steps Improve atom economy Minimize blocking groups
9 Use of Catalysis Use catalysts instead of stoichiometric reagents Increase selectivity and efficiency Industrial catalysts (e.g., Ni, Ziegler–Natta)
10 Design for Degradation Design products that break down safely Prevent environmental persistence Biodegradable materials
Maharashtra State Board: Class 12

Key Points: Characteristic Features of Nanoparticles

No. Characteristic Feature Description Key Effect at Nanoscale Example
1 Colour Optical properties change at nanoscale Materials show different colours than bulk form Gold nanoparticles appear red instead of yellow
2 Surface Area Surface-to-volume ratio increases as particle size decreases Higher reactivity due to more exposed surface atoms Small cubes have greater total surface area than a large cube
3 Catalytic Activity Catalysts become more active due to larger surface area Increased reaction rate and efficiency Pt nanoparticles in hydrogenation; TiO₂, ZnO in photocatalysis
4 Thermal Property (Melting Point) Melting point changes with particle size Smaller particles melt at lower temperatures Sodium clusters melt at lower temperature than bulk sodium
5 Mechanical Properties Strength and hardness increase at nanoscale Enhanced mechanical performance Nano copper and palladium show higher hardness
6 Electrical Conductivity Electrical behaviour differs at nanoscale May behave as conductor or semiconductor Carbon nanotubes show varied conductivity
Maharashtra State Board: Class 12

Definition: Nanoscience

The study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales where properties differ significantly from bulk materials is called nanoscience.

Maharashtra State Board: Class 12

Definition: Nanotechnology

The design, characterization, production and application of structures, devices and systems by controlling shape and size at the nanometer scale is called nanotechnology.

Maharashtra State Board: Class 12

Definition: Nanomaterial

A material having structural components with at least one dimension in the nanometer range (1–100 nm) is called nanomaterial.

Maharashtra State Board: Class 12

Definition: Zero-dimensional Nanostructure

A nanostructure in which all three dimensions are in the nanometer scale is called a zero-dimensional nanostructure.

Maharashtra State Board: Class 12

Definition: One-dimensional Nanostructure

A nanostructure in which two dimensions are in the nanometer scale is called a one-dimensional nanostructure.

Maharashtra State Board: Class 12

Definition: Two-dimensional Nanostructure

A nanostructure in which one dimension is in the nanometer scale is called a two-dimensional nanostructure.

Maharashtra State Board: Class 12

Definition: Nanochemistry

The branch of science dealing with the design and synthesis of materials at the nanoscale with controlled size, shape, structure and composition is called nanochemistry.

Maharashtra State Board: Class 12

Key Points: Applications of Nanomaterials

  • Nanoparticles are used to develop stronger, lighter and smarter materials such as scratch-proof eyeglasses, crack-resistant paints and advanced transport materials.
  • Nanomaterials are widely used in electronic devices, for example in Magnetoresistive Random Access Memory (MRAM).
  • Nanotechnology plays an important role in water purification, where silver nanoparticles are used as effective disinfectants to remove bacteria like E. coli.
  • Nanostructures are used in self-cleaning materials based on the lotus effect, which helps surfaces repel water and dirt.
Maharashtra State Board: Class 12

Key Points: Nanoparticles and Nanotechnology

  • Nanotechnology has revolutionized electronics and computing by improving performance and efficiency of devices.
  • In the energy sector, nanotechnology makes solar power more economical and improves energy storage systems.
  • In the medical field, nanotechnology helps in manufacturing smart drugs and in treating serious diseases like cancer and diabetes with fewer side effects.
  • Despite its advantages, nanotechnology can cause nano pollution and health risks such as lung damage due to inhalation of nanoparticles.
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