The gold number of Galatin . Gum and Starch are 0.005, 0 . 15 and 25 respectively . Which colloid has highest protection power ?

Options

A. Gelatin
B. Starch
C. Gum
D. All have equal protection power

Answer

To determine which colloid has the highest protective power based on their gold numbers, we need to understand the concept of the gold number and its relation to protective power.

### Step-by-Step Solution:

1. **Understanding Gold Number**:
- The gold number is defined as the minimum amount of a protective colloid (in milligrams) required to prevent the coagulation of a standard gold sol (10 ml of gold salt) when a specific amount of an electrolyte (1 ml of 10% NaCl solution) is added.
- A lower gold number indicates a higher protective power of the colloid.

2. **Given Data**:
- Gold number of Gelatin = 0.005
- Gold number of Gum = 0.15
- Gold number of Starch = 25

3. **Comparing Gold Numbers**:
- Gelatin: 0.005 mg
- Gum: 0.15 mg
- Starch: 25 mg

4. **Analyzing Protective Power**:
- Since the gold number is inversely proportional to protective power, the colloid with the lowest gold number will have the highest protective power.
- Comparing the values:
- Gelatin (0.005 mg) has the lowest gold number.
- Gum (0.15 mg) has a higher gold number than gelatin but lower than starch.
- Starch (25 mg) has the highest gold number.

5. **Conclusion**:
- Therefore, the colloid with the highest protective power is **Gelatin**, as it requires the least amount (0.005 mg) to prevent coagulation.

### Final Answer:
The colloid with the highest protection power is **Gelatin**.