The gold number of four colloids A, B, C and D are 0.005, 0.08, 25 and 0.10 respectively. Their protective power has the order:

Options

A. `A gt B gt C gt D`
B. `A gt B gt D gt C`
C. `D gt C gt B gt A`
D. `C gt D gt B gt A `

Answer

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

### Step 1: Understand the Gold Number
The gold number indicates the minimum amount of protective colloid (in milligrams) required to prevent the coagulation of 10 ml of a gold sol when a certain amount of sodium chloride is added. A lower gold number means a higher protective power.

### Step 2: List the Gold Numbers
The gold numbers for the colloids are as follows:
- Colloid A: 0.005
- Colloid B: 0.08
- Colloid C: 25
- Colloid D: 0.10

### Step 3: Compare the Gold Numbers
To determine the protective power, we need to compare the gold numbers. The lower the gold number, the higher the protective power.

### Step 4: Order the Colloids Based on Protective Power
1. Colloid A has the lowest gold number (0.005), so it has the highest protective power.
2. Colloid B has the next lowest gold number (0.08), so it has the second highest protective power.
3. Colloid D has a gold number of 0.10, placing it third.
4. Colloid C has the highest gold number (25), so it has the lowest protective power.

### Step 5: Write the Order of Protective Power
Based on the analysis above, the order of protective power from highest to lowest is:
- A > B > D > C

### Final Answer
The protective power of the colloids in order is: **A > B > D > C**.

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