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Revision Notes
Colloids — Revision Notes
NIOS · Class 12 · Chemistry
Colloids revision notes for NIOS Class 12 Chemistry: 4 topics in quick points. Part of the NIOS Class 12 Chemistry syllabus.
45 questions40 flashcards5 concepts
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Key Topics to Revise
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1. Distinction Between True Solutions, Colloids, and Suspensions
- True solutions have particle size less than 1 nm (homogeneous, transparent)
- Colloidal solutions have particle size between 1-100 nm (heterogeneous, translucent)
- Suspensions have particle size greater than 100 nm (heterogeneous, opaque)
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2. Types of Colloidal Solutions
- Eight types of colloids based on physical states of dispersed phase and dispersion medium
- Solid-Solid: Gemstones, alloys (solid sols)
- Solid-Liquid: Paints, muddy water, gold sol, starch sol (sols)
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3. Classification of Colloids
- Two main classification systems: (1) Based on interaction, (2) Based on molecular size
- Lyophilic colloids: Solvent-loving, have affinity for dispersion medium, easily formed, reversible, stable without stabilizing agents
- Hydrophilic colloids: Lyophilic colloids with water as dispersion medium
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4. Preparation of Colloidal Solutions
- Lyophilic colloids: Direct method - dissolve in suitable medium (starch, gelatin in water; cellulose nitrate in alcohol)
- Lyophobic colloids: Require special preparation methods
- Physical Method 1 - Bredig's Arc Method: Electric arc between metal electrodes in water; heat converts metal to vapor which condenses into colloidal particles
Get complete notes with diagrams and examples
Full NotesKey Concepts
Matter can be classified by particleEvery colloid has two componentsLyophilic colloids ('solventColloidal particles undergo continuousWhen a strong beam of light
Frequently Asked Questions
What are the important topics in Colloids for NIOS Class 12 Chemistry?
Key topics in Colloids include Distinction Between True Solutions, Colloids, and Suspensions, Types of Colloidal Solutions, Classification of Colloids, Preparation of Colloidal Solutions. Study these first, then practise questions on each for the NIOS Class 12 board exam.
How should I revise Colloids for the NIOS Class 12 board exam?
Learn the core ideas first, then work through the 45 practice questions on Colloids. Revise definitions regularly and use flashcards for quick recall before the exam.
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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