Question

The macromolecular colloids of the following are
I. Starch solution II. Sulphur sol III. Synthetic detergent IV. Synthetic rubber

• A. I, II
• B. II, III
• C. III, IV
• D. I, IV

Hint:

Macromolecular colloids are formed by giant polymer molecules such as starch, proteins, nylon and synthetic rubber, whereas detergents form associated colloids and sulphur sol forms multimolecular colloids.

Answer 1

The Correct Option is D

Step 1: Recall the types of colloids by particle size.
Based on the dispersed particle, colloids are classed as multimolecular, macromolecular and associated colloids. We need the macromolecular ones.
Step 2: Define macromolecular colloids.
In a macromolecular colloid the dispersed particles are single very large molecules of high molar mass that are already of colloidal size, such as polymers, both natural and synthetic.
Step 3: Test starch solution.
Starch is a natural polymer of very high molar mass, so dissolving it gives a macromolecular colloid. Statement I qualifies.
Step 4: Test sulphur sol.
A sulphur sol is built from clusters of many small $S$ atoms or molecules grouping together, which makes it a multimolecular colloid, not macromolecular. Statement II does not qualify.
Step 5: Test synthetic detergent.
Detergent molecules gather into micelles only above a certain concentration, so detergents form associated colloids, not macromolecular ones. Statement III does not qualify.
Step 6: Test synthetic rubber and conclude.
Synthetic rubber is a long chain polymer of high molar mass, so it forms a macromolecular colloid. Statement IV qualifies. The macromolecular colloids are I and IV, so the answer is
\[ \boxed{I,\; IV} \]