Question

5.0 mL of [AgI] / Ag$^+$ sol is coagulated by the addition of 15 mL of 0.001 M potassium iodide solution. The flocculation value of potassium iodide is

• A. 6
• B. 5
• C. 3
• D. 4

Hint:

Use the formula: Flocculation value = (millimoles of electrolyte added)/(volume of sol in mL).

Answer 1

The Correct Option is C

Flocculation value = $\dfrac{\text{millimoles of electrolyte}}{\text{volume of sol in mL}}$
Millimoles of KI = $15 \times 0.001 = 0.015$ mmol
Flocculation value = $\dfrac{0.015}{5} = 0.003$ mol/L or 3 mmol/L