The gold number of protective colloids A,B,C and D are 0.02, 0.002, 10 and 30 respectively. then the protective powers of A,B,C and D are in the order

Options

A. `DgtCgtAgtB`
B. `DgtCgtBgtA`
C. `AgtBgtCgtD`
D. `BgtAgtCgtD`

Answer

To determine the protective powers of colloids A, B, C, and D based on their gold numbers, we can follow these steps:

### Step 1: Understand the Concept of Gold Number
The gold number of a protective colloid is defined as the minimum amount of the colloid (in milligrams) required to prevent the coagulation of 10 mL of a gold sol. A lower gold number indicates a higher protective power, meaning that less colloid is needed to stabilize the sol.

### Step 2: List the Gold Numbers
We have the following gold numbers for the colloids:
- A: 0.02
- B: 0.002
- C: 10
- D: 30

### Step 3: Compare the Gold Numbers
To determine the protective power, we can compare the gold numbers:
- A (0.02) < B (0.002) < C (10) < D (30)

### Step 4: Determine the Protective Power Order
Since a lower gold number indicates a higher protective power, we can arrange the colloids in order of their protective power:
- B has the lowest gold number (0.002), thus it has the highest protective power.
- A has the second lowest gold number (0.02), thus it has the second highest protective power.
- C has a higher gold number (10), thus it has lower protective power than A and B.
- D has the highest gold number (30), thus it has the lowest protective power.

### Step 5: Final Order of Protective Powers
Based on the above analysis, the order of protective powers from highest to lowest is:
1. B (highest protective power)
2. A
3. C
4. D (lowest protective power)

### Conclusion
The protective powers of A, B, C, and D are in the order: B > A > C > D.

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