When `6xx10^(-5)g` of a protective colloid was added to `20mL` of a standard gold sol, the precipitation of latter was just prevented on addition of `2mL` of `10%NaCl` solution. The gold number of a protective colloid is

Options

A. 3
B. `3 diamond O^5`
C. 0.06
D. 0.03

Explanation

To calculate the gold number of the protective colloid, we will follow these steps:

### Step 1: Understand the Gold Number Definition
The gold number is defined as the minimum weight (in milligrams) of a protective colloid required to prevent the coagulation of 10 mL of a standard gold sol when 1 mL of a 10% NaCl solution is added.

### Step 2: Identify Given Data
From the question, we have:
- Mass of protective colloid = \(6 \times 10^{-5} \, \text{g}\)
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