In colloid chemistry, fog, clouds, and mist are examples of which type of colloidal system?

Introduction / Context:
This question belongs to basic chemistry and specifically to the topic of colloids. Everyday phenomena such as fog, clouds, and mist are often used to illustrate colloidal systems. Understanding which type of colloid they represent helps students connect theory with real life examples.

Given Data / Assumptions:
- The examples given are fog, clouds, and mist. - Each example consists of tiny liquid water droplets dispersed in air. - The options list common colloid categories such as aerosol, solid sol, foam, and gel.

Concept / Approach:
A colloid is a heterogeneous system in which one substance is finely dispersed in another. When fine liquid droplets are dispersed in a gas, the colloid is called an aerosol. Fog, clouds, and mist are all situations in which liquid water droplets are suspended in air, so they fit the definition of a liquid in gas aerosol.

Step-by-Step Solution:
1. Identify the dispersion medium: in fog, clouds, and mist, air is the medium. 2. Identify the dispersed phase: tiny liquid water droplets. 3. A colloid with liquid dispersed in gas is called an aerosol. 4. Solid sols are solid particles dispersed in liquids, which does not match here. 5. Foam is gas in liquid, such as soap lather, not liquid in gas. 6. Gels are liquids trapped in solid networks, such as jelly, also not relevant. 7. Therefore, fog, clouds, and mist are examples of aerosols.

Verification / Alternative check:
Standard chemistry textbooks list “fog and mist” as examples of liquid in gas aerosols. This classification is consistent across examination question banks and reference materials.

Why Other Options Are Wrong:
Solid sol: Solid in liquid dispersion, for example paint, not liquid in gas. Foam: Gas bubbles dispersed in a liquid, such as whipped cream, not liquid droplets in air. Gel: Liquid dispersed in a solid network, such as gelatin, which is very different from fog or mist.

Common Pitfalls:
Some students confuse aerosol with foam because both relate to gases and liquids. The key is to remember the direction of dispersion: liquid in gas is aerosol, gas in liquid is foam. Remembering that deodorant sprays and fog are examples of aerosols can make this distinction easier.

Final Answer:
Fog, clouds, and mist are examples of the colloidal system called an Aerosol.