Liquid dispersed in a solid
Explanation
A colloid is a heterogeneous mixture where one substance (the dispersed phase) is dispersed as very fine particles within another substance (the dispersion medium). The classification of colloids depends on the physical states (solid, liquid, or gas) of these two components.
Analysis of Options:
- Liquid dispersed in a solid Liquid dispersed in a solid: This system is known as a Gel. In a gel, the liquid particles are trapped within a solid network. Common examples include cheese, butter, and jellies. This is the correct description.
- Solid dispersed in a liquid Solid dispersed in a liquid: This system is known as a Sol. Examples include paints and cell fluids.
- Solid dispersed in a solid dispersed in a solid: This system is known as a Solid Sol. Examples include coloured gemstones and some alloys.
- Liquid dispersed in a liquid dispersed in a liquid: This system is known as an Emulsion. Examples include milk and hair cream.
Key Takeaway:
In a Gel, the dispersion medium is a solid, and the dispersed phase is a liquid.