For the coagulation of `500mL` of arsenious sulphide sol, `2mL` of `1MNaCl` is required. What is the flocculation value of `NaCl` ?

Explanation

To find the flocculation value of NaCl for the coagulation of arsenious sulphide sol, we can follow these steps:

### Step 1: Understand the Given Information
We know that for the coagulation of 500 mL of arsenious sulphide sol, 2 mL of 1 M NaCl is required.

### Step 2: Calculate the Millimoles of NaCl Used
To calculate the number of millimoles of NaCl used, we can use the formula:
\[ \text{Millimoles} = \text{Molarity (M)} \times \text{Volume (mL)} \]
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