The cogulation of 100 mL of colloidal solutionof gold is completely prevented by additionof 0.25 g of substance "X" to it before addition of 1 mL of `10%` NaCl solution. The gold number of substance 'X' is :

Options

A. `0.25`
B. 25
C. 250
D. 2.5

Answer

B

Explanation

Mass of protecting colloid 'X' to be added to prevent the coagulation of 100 mL of colloidal solution of gold = 0.25 g.
Gold number of protecting colloid 'X' = 25 mg