which of the following is most effective in coagulating ferric hydroxide sol?
a. `KCl`
b. `FeCl_(3)`
c. `Na_(2)SO_(4)`
d. `K_(3)[Fe(CN)_(6)]`

Explanation

To determine which of the given electrolytes is most effective in coagulating ferric hydroxide sol (Fe(OH)₃), we can follow these steps:

### Step 1: Understand the Concept of Coagulation
Coagulation refers to the process where colloidal particles aggregate to form larger particles, which can then settle out of the solution. The effectiveness of an electrolyte in coagulating a colloidal solution is influenced by its charge and valency.

### Step 2: Identify the Charge of the Colloidal Particles
Ferric hydroxide (Fe(OH)₃) is a colloidal sol that has positively charged particles (Fe³⁺ ions). To coagulate this sol, we need to introduce an electrolyte that can provide negatively charged ions to neutralize the positive charge of the colloidal particles.

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