Question

Which of the following ion exhibits maximum power of coagulation for positively charged Sol ?

• A. SO$_4^{2-}$
• B. PO$_4^{3-}$
• C. Cl$^-$
• D. [Fe(CN)$_6$]$^{4-}$

Hint:

Coagulation Power $\propto (\text{Charge})^4$. More charge = Better coagulation.

Answer 1

The Correct Option is D

Step 1: Hardy-Schulze Rule
The coagulating power of an ion is directly proportional to the fourth power of its valency.
Step 2: Analysis
To coagulate a **positively** charged sol, we need a **negatively** charged ion (anion). - (A) Valency $= 2$ - (B) Valency $= 3$ - (C) Valency $= 1$ - (D) Valency $= 4$
Step 3: Conclusion
The ion with the highest charge (magnitude) will have the maximum coagulating power.
Final Answer: (D)