gold number is a term used in colloidal chemistry. it is defined as the number of milli grams of the protective colloid that will just prevent the coagulation of 10ml gold sol on the addition of 1 ml 10 percent sodium chloride solution.
coagulation of gold sol is indicated by colour change from red to blue when particle size just increases.
eg. gold number for some protective colloids are given below
gelatin:0.005-0.01
Haemoglobin :0.03-0.07
egg albumin:0.1-0.2
potato starch:20-25
hope u are satisfied with the answer. for further clarification of technical terms please refer surface chemistry.
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