What is a colloidal solution?

A colloidal solution is defined as a heterogeneous mixture that contains microscopic particles dispersed throughout a solvent. These particles, which are larger than those typically found in a true solution but small enough to remain suspended, do not settle out over time. This characteristic gives colloids their unique properties, such as the ability to scatter light, often observed as the Tyndall effect.

In a colloid, the dispersed particles can be solid, liquid, or even gas, and they can interact with the solvent in complex ways. The microscopic size of the particles means that they cannot easily be seen with the naked eye, and they remain evenly distributed due to Brownian motion, which helps prevent sedimentation.

While a colloidal solution is not homogeneous in the same way a true solution is, it is stable within the context of its particle interactions in the solvent. This distinguishes it from a true solution where solute molecules are completely dissolved and evenly distributed at a molecular level, as well as from other mixtures that do not involve such small particles. Therefore, the correct understanding of colloidal solutions highlights their unique nature and behavior, aligning perfectly with the characteristics described in the chosen answer.