Question

Which of the following is incorrectly matched?

• A. Multi molecular colloid - S$_8$
• B. Macro molecular colloid - enzyme
• C. As$_2$S$_3$ sol - positively charged sol
• D. Starch sol - lyophilic sol

Hint:

Multi-molecular colloids are composed of small particles, macro-molecular colloids consist of large molecules like enzymes, and lyophilic sols are those that attract the solvent.

Answer 1

The Correct Option is C

To determine which option is incorrectly matched, let's analyze each statement based on our understanding of colloids:

• Multi molecular colloid - S₈: Multi molecular colloids consist of aggregates of atoms or molecules that are grouped together in a colloidal size. S₈, sulfur, forms such aggregates, so this match is correct.
• Macro molecular colloid - enzyme: Macromolecular colloids involve individual macromolecules dispersed in a medium. Enzymes, which are large proteins, form such colloidal systems, thus this match is accurate.
• As₂S₃ sol - positively charged sol: Arsenic trisulfide (As₂S₃) sols are usually negatively charged. This makes the statement of being positively charged incorrect.
• Starch sol - lyophilic sol: Lyophilic sols are colloidal solutions where the colloidal particles have affinity for the solvent. Starch forms lyophilic colloids, confirming this match is correct.

Therefore, the incorrectly matched option is: As₂S₃ sol - positively charged sol.

Answer 2

A colloid is a substance made up of particles that are intermediate in size between those of a true solution and those of a suspension. Here’s a breakdown of the matching options: 
Step 1:  - Multi molecular colloid - S$_8$: S$_8$ (sulfur) is a multi-molecular colloid because it consists of a large number of smaller molecules.
Hence, this match is correct. 
Step 2:  - Macro molecular colloid - enzyme: Enzymes are large macromolecules and are typically classified as macro-molecular colloids. 
Thus, this match is correct. 
Step 3: - As$_2$S$_3$ sol - positively charged sol: As$_2$S$_3$ (arsenic trisulfide) is a negative sol, not a positively charged sol. 
Hence, this match is incorrect. 
Step 4: - Starch sol - lyophilic sol: Starch forms a lyophilic (solvent-attracting) sol, which is a correct match.
Thus, the incorrect match is As$_2$S$_3$ sol - positively charged sol, making option (3) the correct answer.