On addition of 1ml solution of 10% NaCl to 10ml gold sol in the presence of 0.0250gm of starch, the coagulation is just prevented Starch has the following gold number

The minimum milligrams of protective colloid required to prevent the coagulation of10ml of gold sol by the addition to 1ml of 10% NaCl solution is called Gold number           10ml goldsol is prevented from coagulation by the addition of 0.025 grams of starch Gold number= 0.025 X 103 =25