Grade 12
  1. Solid state  1.1. Classification of solids  1.2. Crystal Lattice and Unit Cell  1.3. Packing Efficiency  1.4. Density of unit cell  1.5. Imperfections in solids (point and line defects)  1.6. Electrical Properties of Solids (Conductors, Insulators and Semiconductors)  1.7. Magnetic Properties of Solids (Diamagnetic, Paramagnetic and Ferromagnetic Materials)
  2. Solution  2.1. Types of Solutions (Homogeneous and Heterogeneous)  2.2. Expressing concentration of solutions (mass %, volume %, molarity, molality, normality, mole fraction)  2.3. Solubility of solids and gases in liquids (Henry's law)  2.4. Raoult's Law and Ideal and Non-Ideal Solutions  2.5. Syndrome properties  2.6. Abnormal molar mass and Van't Hoff factor
  3. Electrochemistry  3.1. Electrochemical cells (galvanic and electrolytic cells)  3.2. Galvanic cell and EMF of the cell  3.3. Standard electrode potential and electrochemical series  3.4. Nernst equation and its applications  3.5. Conductivity and electrolytic cells (specific, molar and equivalent conductivity)  3.6. Kohlrausch's law and its applications  3.7. Batteries (primary and secondary cells)  3.8. Corrosion and its prevention
  4. Chemical kinetics  4.1. Rate of chemical reaction  4.2. Factors affecting the reaction rate (concentration, temperature, catalyst, surface area)  4.3. Order and molecularity of the reaction  4.4. Integrated Rate Equations (Zero, First and Second Order)  4.5. Half-life of a reaction  4.6. Collision theory and activation energy  4.7. Arrhenius equation and its applications
  5. Surface chemistry  5.1. Adsorption and its types (Physicosorption and Chemisorption)  5.2. Catalysis and its types (homogeneous and heterogeneous)  5.3. Colloids and their properties (Tyndall effect, Brownian motion, coagulation)  5.4. Emulsions and gels  5.5. Applications of Colloids
  6. General principles and processes of separation of elements  6.1. Presence of metals and minerals  6.2. Concentration of ores (gravity separation, froth flotation, magnetic separation)  6.3. Extraction of raw metals (roasting, calcination, reduction)  6.4. Thermodynamic and electrochemical principles of metallurgy  6.5. Refining of metals
  7. P-block elements  7.1. Group 15 elements (nitrogen and phosphorus)  7.2. Group 16 Elements (Oxygen, Sulphur and their Compounds)  7.3. Group 17 Elements (Halogens and their Compounds)  7.4. Group 18 Elements  7.5. Properties and Trends in p-Block Elements  7.6. Important compounds of p-block elements (ammonia, phosphine, sulphuric acid, hydrochloric acid)  7.7. Interhalogen compounds and their applications
  8. d-block and f-block elements  8.1. General Properties of Transition Metals  8.2. Properties of Inner Transition Metals (Lanthanoids and Actinoids)  8.3. Lanthanoid and actinoid contractions  8.4. Coordination Chemistry of d-Block Elements
  9. Coordination compounds  9.1. Werner's theory and modern concepts  9.2. Coordination number and type of ligand  9.3. Nomenclature of Coordination Compounds  9.4. Isomerism (geometrical and optical) in coordination compounds  9.5. Bonding in Coordination Compounds (Valence Bond Theory and Crystal Field Theory)  9.6. Stability and applications of coordination compounds in medicine and industry
  10. Haloalkanes and haloarenes  10.1. Classification and nomenclature of haloalkanes and haloarenes  10.2. Physical and Chemical Properties of Haloalkanes and Haloarenes  10.3. Mechanism of Nucleophilic Substitution Reactions (SN1 and SN2)  10.4. Uses and environmental effects (ozone depletion, CFCs)
  11. Alcohol, phenol and ether  11.1. Structure and classification of alcohols, phenols and ethers  11.2. Preparation and properties of alcohols  11.3. Preparation and properties of phenol  11.4. Preparation and properties of ethers  11.5. Chemical Reactions and Uses
  12. Aldehydes, ketones and carboxylic acids  12.1. Structure and nomenclature in aldehydes, ketones and carboxylic acids  12.2. Preparation and properties of aldehydes and ketones  12.3. Chemical reactions in aldehydes, ketones and carboxylic acids (nucleophilic addition, oxidation and reduction)  12.4. Preparation and Properties of Carboxylic Acids  12.5. Chemical Reactions and Uses of Carboxylic Acids
  13. Nitrogen-containing organic compounds  13.1. Amines (classification, structure, basicity)  13.2. Preparation and properties of amines  13.3. Reactions of Amines (Diazotization, Carbylamine Reaction)  13.4. Diazonium salts and their applications in paint industry
  14.1. Carbohydrates (classification and properties)  14.2. Proteins (Structure and Function)  14.3. Enzymes (Mechanism and Function)  14.4. Nucleic acids (DNA and RNA)  14.5. Vitamins and hormones
  15. Polymer  15.1. Classification of Polymers (Addition, Condensation, Copolymers)  15.2. Types of polymerization (free radical, ionic, condensation)  15.3. Important Polymers and Their Uses  15.4. Biodegradable and non-biodegradable polymers
  16. Chemistry in Everyday Life  16.1. Drugs and their classification (analgesics, antipyretics, antibiotics, antacids)  16.2. Chemicals in food and cosmetics (preservatives, artificial sweeteners, antioxidants)  16.3. Cleaning agents and detergents (soaps, synthetic detergents, surfactants)  16.4. Environmental Chemistry (Pollution, Green Chemistry, Sustainable Chemistry)

Grade 12 → Surface chemistry ↓


Applications of Colloids


Colloids are an important topic in surface chemistry and have many practical applications in various fields such as pharmaceuticals, the food industry, biotechnology, and environmental science. In simple terms, a colloid is a mixture where one substance is evenly dispersed throughout another. This unique structure gives the materials unique properties, making colloids incredibly useful in a variety of industries.

Understanding colloids

To understand the applications of colloids, we must first understand what colloids are. At its core, a colloid is a heterogeneous mixture where one phase is dispersed within another continuous phase as tiny particles, droplets, or bubbles. The dispersed phase typically consists of particles ranging in size from 1 nanometer to 1,000 nanometers. Because of their size, these particles are not large enough to settle under the force of gravity, nor are they small enough to qualify as a solution.

Colloids may be classified based on the phases involved:

  • Sol: A solid substance dispersed in a liquid. For example, paint.
  • Gel: A fluid dispersed in a solid substance. For example, jelly.
  • Emulsion: A liquid dispersed in another liquid. For example, mayonnaise.
  • Aerosol: A solid or liquid dispersed in a gas. For example, fog or smoke.
  • Foam: A gas expanded within a liquid or solid. For example, whipped cream or Styrofoam.

Physical properties of colloids

The physical properties of colloids bring about their practical applications. Some of the primary physical characteristics include:

  • Tyndall effect: Scattering of light by colloidal particles. This effect is observed when a beam of light passes through a colloid and becomes visible due to scattering by the dispersed phase. In laboratories, the Tyndall effect is used to separate colloids from true solutions.
  • Browning motion: Colloidal particles are in continuous random motion due to the influence of the molecules of the dispersion medium. This motion prevents the particles from settling.
  • Stability: Colloids are relatively stable and can maintain their dispersion without the particles settling.
  • Coagulation: Colloids may be destabilized or coagulated by the addition of suitable electrolytes or by changing the temperature.

Basic colloid examples

To explain the concepts using the basic visual model, here are some diagrammatic examples:

    
+-------------------------------------------+
| Colloidal System Examples                 |
+-------------------------------------------+
| Type        | Dispersed | Dispersing      |
|             | Phase     | Medium          |
+-------------------------------------------+
| Sol         | Solid     | Liquid          |
| (eg,        | (eg,      | (eg, water)     |
| Paint)      | Pigments) |                 |
+-------------------------------------------+
| Gel         | Liquid    | Solid           |
| (eg,        | (eg,      | (eg, gelatin)   |
| Jelly)      | Water)    |                 |
+-------------------------------------------+
| Emulsion    | Liquid    | Liquid          |
| (eg,        | (eg,      | (eg, oil)       |
| milk)       | Water)    |                 |
+-------------------------------------------+
| Aerosol     | Liquid/   | Gas             |
| (eg,        | Solid (eg,| (eg, air)       |
| Fog,        | dust/fog) |                 |
| Smoke)      |           |                 |
+-------------------------------------------+
| Foam        | Gas (eg,  | Liquid/Solid    |
| (eg,        | Air)      | (eg, water or   |
| whipped     |           | polymer)        |
| cream)      |           |                 |
+-------------------------------------------+

Colloids in the food industry

The food industry relies heavily on colloids for the texture, consistency, and stability of products. Many food items such as milk, butter, cheese, jam, jelly, and mayonnaise are colloidal in nature. Let us explore some colloidal applications in the food industry:

  • Milk: Milk is a classic example of an emulsion where fat droplets are dispersed in a water-based medium. The homogenization process in the dairy industry ensures that the milk fat pellets remain stable and do not separate from the rest of the milk.
  • Jelly: Jelly exhibits the gel type of colloids, where the liquid (water) is dispersed within the solid matrix of pectin, forming a semi-solid consistency.
  • Butter: Butter is a water-in-oil emulsion. During its manufacture, water droplets diffuse into the continuous phase of fat, resulting in a spreadable, stable product.
  • Mayonnaise: Example of a thick and stable emulsion in which oil is dispersed within an air-gelled continuous phase of water and egg-based proteins, giving a thick consistency.

Colloids in pharmaceuticals

In the pharmaceutical industry, colloids have many applications, ranging from drug delivery to improving the efficiency and effectiveness of drugs. Colloids can be formulated to have specific shapes, surfaces, and properties, making them particularly useful in medical applications.

  • Drug delivery systems: Colloidal particles are used in designing drug delivery systems such as liposomes, micelles, and nanoparticulate delivery systems. These systems can encapsulate drug particles, protecting them from degradation until they reach the specific site of action in the body.
  • Controlled release: Colloidal formulations can be formulated for slow, controlled release of drugs over a period of time, increasing drug efficacy and reducing side effects.
  • Increased bioavailability: Some drugs are poorly soluble in water. Colloidal suspensions and emulsions can improve the bioavailability and absorption of these drugs.

Colloids in the environment

Colloids play important roles in environmental processes, especially in water treatment and pollution management. By understanding and harnessing the properties of colloids, we can develop solutions to manage pollution and improve environmental health.

  • Water treatment: In water treatment processes, colloidal particles are removed through coagulation and flocculation, making water safe to drink. Chemical coagulation causes colloidal impurities in water to aggregate and be easily removed.
  • Pollution control: Colloids can help control environmental pollution by adsorbing harmful particles and gases. For example, using colloidal clay particles, it is possible to remove pollutants from water and soil.
  • Soil fertility: Soil colloids play a vital role in retaining nutrients and maintaining fertility. The absorption of nutrients by colloidal particles of soil helps in the natural ecosystem and plant growth.

Colloids in technology and industry

Technology and industry use colloids for a variety of products and applications due to their unique properties.

  • Paints and inks: Paints and inks are examples of colloidal dispersions in which pigment particles are dispersed in a liquid medium. This dispersion ensures uniform color and adhesion to surfaces.
  • Cosmetics: Colloids are widely used in the cosmetic industry for creams, lotions, and other emulsion-based products. By dispersing active ingredients, cosmetics can provide smooth textures and effective results for skin and hair care.
  • Nano-coatings: Colloids are important in creating nanostructured coatings, which serve purposes such as anti-reflection, corrosion protection, and self-cleaning in industrial applications.

Colloids in biotechnology

Colloids have unique applications in biotechnology where they aid in research and product development.

  • Bioreactors: Colloid-based stabilization techniques are used for effective design of bioreactors, ensuring successful production of enzymes and bioproducts.
  • Gene therapy: Colloidal carriers serve as a promising means for transporting genetic material into cells, making them essential for developing effective gene therapy techniques.

Conclusion

Colloids serve an indispensable function in many industries due to their unique properties, such as stability, ability to provide controlled drug delivery, nutrient retention in soil, and many others. By understanding the different forms of colloids and their applications, researchers and industry can further harness their potential to improve existing processes and develop new technologies. The exploration of colloids continues to be a dynamic field with exciting new applications in a variety of fields.


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Applications of Colloids

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