Which of the following best describes a colloid in an aqueous solution?

• A. A solution in which the solute is insoluble and forms a separate layer.
• B. A heterogeneous mixture in which large particles settle out upon standing.
• C. A mixture in which particles are dispersed throughout the solvent and remain evenly distributed without settling, with particle sizes between 1 nm and 1000 nm.
• D. A homogeneous mixture in which solute particles are completely dissolved and have particle sizes less than 1 nm.

Answer: (C)

Verified step by step guidance

1. Understand the definition of a colloid: it is a mixture where particles are dispersed throughout a solvent but do not settle out over time.
2. Recognize that colloidal particles have sizes between 1 nm and 1000 nm, which is larger than typical dissolved molecules but smaller than particles in suspensions.
3. Distinguish colloids from solutions: solutions have particles smaller than 1 nm that are completely dissolved and homogeneous.
4. Distinguish colloids from suspensions: suspensions have larger particles that are heterogeneous and settle out upon standing.
5. Conclude that the best description of a colloid in an aqueous solution is a mixture with dispersed particles sized between 1 nm and 1000 nm that remain evenly distributed without settling.