Gold Numbers of Substances A, B, and C

The gold numbers of substances A, B, and C are 0.05, 0.8, and 0.3, respectively. The substance with the maximum protective power can be determined by comparing these gold numbers. The gold number is a measure of the protective power of a substance against the coagulation of a gold sol. A lower gold number indicates a higher protective power.

Comparing the Gold Numbers
To determine the substance with the maximum protective power, we need to compare the gold numbers of substances A, B, and C.

- Substance A: Gold Number = 0.05
- Substance B: Gold Number = 0.8
- Substance C: Gold Number = 0.3

Substance with Maximum Protective Power
From the given gold numbers, we can observe that substance A has the lowest gold number of 0.05. This indicates that substance A has the highest protective power among the three substances.

Explanation
The gold number is determined by the amount of a protective colloid required to prevent the coagulation of a gold sol. A lower gold number indicates that a smaller amount of the substance is needed to prevent coagulation, which implies a higher protective power.

In this case, substance A with a gold number of 0.05 requires the least amount of protective colloid to prevent coagulation. This suggests that substance A has a higher ability to stabilize the gold sol and inhibit the aggregation of gold particles compared to substances B and C.

The protective power of a substance is crucial in various applications, especially in colloidal systems, where stability is essential. A substance with high protective power can maintain the dispersion of particles and prevent their aggregation, ensuring the desired properties and functionality of the system.

Therefore, based on the given gold numbers, substance A has the maximum protective power among substances A, B, and C.