Question

Gold number is the measure of protective power protective collide

Answer 1

Answer:

Explanation:

Gold Number is a term used in colloidal chemistry. It is defined as the minimum amount of protective colloid in milligrams which prevents a color change from red to violet of 10ml gold sol by the addition of 1 ml of 10%NaCl solution.

Answer 2

Zsigmondy introduced a term called gold number to describe the protective power of different colloids. This is defined as, “weight of the dried protective agent in milligrams, which when added to 10 ml of a standard gold sol (0.0053 to 0.0058%) is just sufficient to prevent a colour change from red to blue on the addition of 1 ml of 10 % sodium chloride solution, is equal to the gold number of that protective colloid.”

Thus, smaller is the gold number, higher is the protective action of the protective agent.

Table: Gold numbers of some hydrophilic substances

Hydrophilic substance Gold number Hydrophilic substance Gold number

Gelatin 0.005 - 0.01 Sodium oleate 0.4 – 1.0

Sodium caseinate 0.01 Gum tragacanth 2

Hamoglobin 0.03 – 0.07 Potato starch 25

Gum arabic 0.15 – 0.25    

ok