Gold Number (Protective Colloids) (Gold number = mg protective colloid per standard gold sol + NaCl test (NCERT definition))
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Gold number = mg protective colloid per standard gold sol + NaCl test (NCERT definition)
What each symbol means
| Symbol | What it stands for |
|---|---|
| gold number | Minimum milligrams of protective (lyophilic) colloid to prevent coagulation of 10 mL gold sol on adding 1 mL 10% NaCl; lower value ⇒ higher protecting power |
When to use this
Standardized test: 10 mL gold sol, 1 mL 10% NaCl. Protective colloids (gelatin, starch, etc.) stabilize lyophobic sols. Lower gold number ⇒ greater protecting power.