0.00001g of gelatin is required to be added to 100cm3 of a standard gold sol to just prevent its coagulation by the addition of 1cm3 of 10% NaCl solution to it.hence the gold number of gelatin is

The gold number is a measure of the protective colloid's effectiveness in preventing the coagulation of a colloidal solution, such as a gold sol. In your case, we need to calculate the gold number of gelatin based on the information provided about the amount of gelatin required to stabilize the gold sol against coagulation when a specific amount of NaCl is added.

Understanding the Components

To break this down, we have:

• Amount of gelatin: 0.00001 g
• Volume of gold sol: 100 cm³
• Volume of NaCl solution added: 1 cm³
• Concentration of NaCl solution: 10%

Calculating the Amount of NaCl

First, let's determine how much NaCl is present in the 1 cm³ of 10% solution. A 10% solution means there are 10 grams of NaCl in 100 cm³ of solution. Therefore, in 1 cm³:

Amount of NaCl = 10 g/100 cm³ × 1 cm³ = 0.1 g

Gold Number Calculation

The gold number is defined as the number of grams of protective colloid (in this case, gelatin) required to prevent the coagulation of a standard gold sol when a specific amount of an electrolyte (like NaCl) is added. The formula for calculating the gold number (GN) is:

GN = (mass of gelatin in grams) / (mass of NaCl in grams)

Substituting the values we have:

GN = 0.00001 g / 0.1 g = 0.0001

Final Result

Thus, the gold number of gelatin is 0.0001. This indicates that a very small amount of gelatin is required to effectively stabilize the gold sol against coagulation when a known quantity of NaCl is introduced. This property is crucial in various applications, including pharmaceuticals and food science, where colloidal stability is essential.