Correct Option
The correct option isFog
Explanation
Colloids are heterogeneous mixtures where one substance (the dispersed phase) is suspended throughout another substance (the dispersion medium). The classification of colloids depends on the physical states (solid, liquid, or gas) of these two phases. An Aerosol is defined as a colloid where the dispersion medium is a gas.
Option Analysis
- Shaving cream Shaving cream: This is an example of a Foam, where the dispersed phase is a gas and the dispersion medium is a liquid.
- Milk: This is an example of an Emulsion, where both the dispersed phase and the dispersion medium are liquids (liquid fat globules dispersed in water).
- Fog: This is an example of a Liquid Aerosol. Here, fine liquid water droplets (dispersed phase) are suspended in air (dispersion medium, which is a gas). Clouds and mist are also examples of this category.
- Sponge: This is an example of a Solid Foam, where the dispersed phase is a gas and the dispersion medium is a solid.
Key Takeaway
Aerosols are colloids in which the dispersion medium is a gas. If the dispersed phase is a solid, it is a solid aerosol (e.g., smoke); if the dispersed phase is a liquid, it is a liquid aerosol (e.g., fog, mist).