Question

The correct order of coagulating power of the following ions to coagulate the positive sol is
I $[\text{Fe}(\text{CN})_6]^{4-}$, II $\text{Cl}^-$, III $\text{SO}_4^{2-}$

• A. I \(>\) II \(>\) III
• B. III \(>\) II \(>\) I
• C. I \(>\) II \(=\) III
• D. I \(>\) III \(>\) II

Hint:

The Hardy-Schulze rule states that the coagulating power of an ion increases with the magnitude of its charge.

Answer 1

The Correct Option is D

To coagulate a positive sol, negatively charged ions (anions) are used. According to the Hardy-Schulze rule, the coagulating power of an ion is proportional to the magnitude of its charge. The charges are: \([\text{Fe}(\text{CN})_6]^{4-}\) (\(-4\)), \(\text{Cl}^-\) (\(-1\)), and \(\text{SO}_4^{2-}\) (\(-2\)). Thus, the order of coagulating power is: \[ [\text{Fe}(\text{CN})_6]^{4-}>\text{SO}_4^{2-}>\text{Cl}^- \] In terms of the labels: I \(>\) III \(>\) II. This matches option 4. Thus, the correct answer is I \(>\) III \(>\) II.