Colloids MCQs Quiz | Class 9
Test your understanding of Class IX Science (Unit I: Matter – Its Nature and Behaviour) with this focused quiz on Colloids. Covering essential concepts like definition, properties (stability and appearance), and common examples (like Tyndall effect), these 10 MCQs are designed to help you prepare for exams. Complete the quiz to view your score and download the solution PDF.
Understanding Colloids
Colloids are heterogeneous mixtures where the particle size is intermediate between true solutions and suspensions. Although they often appear homogeneous to the naked eye (like milk), the particles are large enough to scatter a beam of light, a phenomenon known as the Tyndall effect.
Key Properties
- Particle Size: Generally ranges between 1 to 100 nanometers.
- Visibility: Particles are too small to be seen individually by the naked eye but can be observed with an ultramicroscope.
- Filtration: Colloidal particles can pass through ordinary filter paper but can be separated by special semi-permeable membranes or centrifugation.
- Stability: Colloids are quite stable; the particles do not settle down when left undisturbed.
Components of a Colloid
A colloidal solution has two phases:
- Dispersed Phase: The solute-like component or the dispersed particles (e.g., fat globules in milk).
- Dispersion Medium: The component in which the dispersed phase is suspended (e.g., water in milk).
Common Types and Examples
| Dispersed Phase | Dispersion Medium | Type | Examples |
|---|---|---|---|
| Liquid | Gas | Aerosol | Fog, Clouds, Mist |
| Solid | Gas | Aerosol | Smoke, Automobile exhaust |
| Gas | Liquid | Foam | Shaving cream |
| Liquid | Liquid | Emulsion | Milk, Face cream |
| Solid | Liquid | Sol | Milk of Magnesia, Mud |
Quick Revision Points
- The scattering of light by colloidal particles is called the Tyndall Effect.
- Centrifugation is a common method used to separate colloidal particles (like cream from milk).
- Brownian motion describes the random zig-zag movement of colloidal particles.
Extra Practice Questions
- Define the term ‘Emulsion’ with an example.
- Why does the path of light become visible in a colloidal solution?
- Differentiate between a Sol and a Gel.
- Is blood a colloid? If yes, what is the dispersed phase?
- How does particle size influence the stability of a mixture?
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