Gold numbers of some colloids are : Gelatin : 0.005 - 0.01, Gum Arabic : 0.15 - 0.25; Oleate : 0.04 - 1.0; Starch : 15 - 25. Which among these is a better protective colloid ?

Question

The half-life of $^{65}$Zn is 245 days. After $x$ days, 75% of the original activity remained. The value of $x$ in days is __________ (Nearest integer).}
(Given: $\log 3 = 0.4771$ and $\log 2 = 0.3010$)

Answer 1

To determine which colloid is a better protective colloid, we need to understand the concept of the "gold number." The gold number is a measure of the protective power of a colloid. It is defined as the minimum amount of a protective colloid in milligrams required to prevent the coagulation (or precipitation) of 10 mL of a standard gold sol by the addition of 1 mL of 10% sodium chloride solution. A lower gold number indicates a better protective colloid because it means that a smaller amount of the colloid is required to provide protection.

Let's analyze the given gold numbers for each colloid:

Gelatin: 0.005 - 0.01
Gum Arabic: 0.15 - 0.25
Oleate: 0.04 - 1.0
Starch: 15 - 25

From these values, Gelatin has the smallest range of gold numbers (0.005 - 0.01), indicating that it requires the least amount to effectively protect against coagulation. Therefore, it is the best protective colloid among the options provided.

To conclude, Gelatin is a better protective colloid than the other substances listed because it has the lowest gold number.

Answer 2

To determine which colloid is a better protective colloid, we need to understand the concept of the "gold number." The gold number is a measure of the protective power of a colloid. It is defined as the minimum amount of a protective colloid in milligrams required to prevent the coagulation (or precipitation) of 10 mL of a standard gold sol by the addition of 1 mL of 10% sodium chloride solution. A lower gold number indicates a better protective colloid because it means that a smaller amount of the colloid is required to provide protection.

Let's analyze the given gold numbers for each colloid:

Gelatin: 0.005 - 0.01
Gum Arabic: 0.15 - 0.25
Oleate: 0.04 - 1.0
Starch: 15 - 25

From these values, Gelatin has the smallest range of gold numbers (0.005 - 0.01), indicating that it requires the least amount to effectively protect against coagulation. Therefore, it is the best protective colloid among the options provided.

To conclude, Gelatin is a better protective colloid than the other substances listed because it has the lowest gold number.

Gold numbers of some colloids are : Gelatin : 0.005 - 0.01, Gum Arabic : 0.15 - 0.25; Oleate : 0.04 - 1.0; Starch : 15 - 25. Which among these is a better protective colloid ?

The Correct Option is A

Solution and Explanation

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