Surface Chemistry

Question

Gold numbers of some colloids are : Gelatin : 0.005 - 0.01, Gum Arabic : 0.15 - 0.25; Oleate : 0.04 - 1.0; Starch : 15 - 25. Which among these is a
better protective colloid ?

Accepted Answer

Option A. Gold number of a protective colloid is a minimum weight of it in milligrams which must be added to 10 ml of a standard red gold sol. so that no coagulation of the gold sol. (i.e. change of colour from red to blue) takes place when 1 ml of 10% sodium chloride solution is rapidly added to it. Obviously, smaller the gold number of a protective colloid, the greater is the protective actioin.

More on Surface Chemistry

Surface Chemistry

More on Surface Chemistry