More Info. on Colloids

Zigmondy introduced the term gold number to evaluate quantitatively the protective power of different lyophilic colloids. It may be defined as ‘least quantity of protective colloid in milligrams, which is just sufficient to prevent the coagulation of 10 ml of standard gold sol (containing 0.0053% gold) by the rapid addidition of 1 ml of 10% NaCl solution. The Coagulation of gold sol is indicated by change in color from red to violet. Thus small the gold number, the greater is protective power of lyophilic colloid.

Colloid is a heterogeneous mixture in which particle size is intermediate of true solution and suspension. Smoke from a fire is example of colloidal system in which tiny particles.

Colloid is a heterogeneous mixture in which particle size is intermediate of true solution and suspension. Smoke from a fire is example of colloidal system in which tiny particles.