Question

Which of the following is an example of a multi molecular colloid?

• A. Sulphur sol
• B. Starch sol
• C. Natural rubber sol
• D. Soap sol

Hint:

Distinguish between multimolecular, macromolecular, and associated colloids based on the size and formation of the colloidal particles. Remember the key examples for each type: aggregation of small molecules for multimolecular (e.g., sulphur sol), large molecules as dispersed phase for macromolecular (e.g., starch sol), and micelle formation for associated (e.g., soap sol).

Answer 1

The Correct Option is A

Colloids can be classified based on the nature of the dispersed phase particles into multimolecular, macromolecular, and associated colloids.
- **Multimolecular colloids:** These colloids are formed by the aggregation of a large number of atoms or small molecules (diameter<1 nm) to form colloidal particles having a size in the colloidal range (1-1000 nm).
Examples include sols of gold, sulphur, and metal sulphides.
- **Macromolecular colloids:** In these colloids, the dispersed phase particles are macromolecules (large molecules) having colloidal dimensions.
These macromolecules have high molecular masses.
Examples include starch, proteins, cellulose, and synthetic polymers like rubber and nylon.
- **Associated colloids (Micelles):** These colloids behave as normal strong electrolytes at low concentrations but exhibit colloidal properties at higher concentrations due to the formation of aggregates of molecules called micelles.
Examples include soaps and detergents.
Based on these definitions: - **Sulphur sol:** Sulphur sol is formed by the aggregation of a large number of \( S_8 \) molecules.
Thus, it is a multimolecular colloid.
- **Starch sol:** Starch is a macromolecule.
Its sol is a macromolecular colloid.
- **Natural rubber sol:** Natural rubber is a polymer, a macromolecule.
Its sol is a macromolecular colloid.
- **Soap sol:** Soap forms micelles at higher concentrations, which are associated colloids.
Therefore, the example of a multimolecular colloid among the given options is Sulphur sol.