Understanding Coagulation in Dispersed Systems

This question examines the effect of electrolytes on dispersed systems, specifically focusing on coagulation.

Statement Analysis

• Assertion A: States that high electrolyte concentration leads to the coagulation of dispersed systems. This is a known phenomenon in colloidal chemistry where adding electrolytes neutralizes the charge on colloidal particles, causing them to aggregate and settle. Therefore, Assertion A is correct.
• Reason R: Explains that coagulation occurs because repulsive forces among particles are greatly reduced. When electrolytes are added, their ions neutralize the surface charges of the dispersed particles. This reduction in charge diminishes the electrostatic repulsion between particles, allowing attractive forces (like van der Waals forces) to dominate, leading to coagulation. Therefore, Reason R is correct.

Evaluating the Explanation

Reason R directly explains the mechanism behind Assertion A. The reduction of repulsive forces is the cause of coagulation when electrolyte concentration is high enough to neutralize particle charges effectively.

Therefore, both statements are correct, and Reason R provides the correct explanation for Assertion A.

Conclusion

Based on the analysis, the most appropriate answer is that both Assertion A and Reason R are correct, and R is the correct explanation of A.