Gold number of gum arabic is 0.15. The amount of gum arabic required to protect 100mL of red gold sol from coagulation by 10mL of 10% NaCl solution is

Gold number of Gum Arabic =0.15 0.15 mg of Lyophilic solid needed in 10 ml 10 ml —0.15mg 100ml—? 100×0.1510=1.5mg 1.5 mg of Gold will be needed to protect 100 ml of red color