Hardy–Schulze Rule (Coagulation of Colloids) (Coagulating power ∝ |charge|^n; classical As2S3 negative sol ~ sixth power in counter-ion)
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Coagulating power ∝ |charge|^n; classical As2S3 negative sol ~ sixth power in counter-ion charge
What each symbol means
| Symbol | What it stands for |
|---|---|
| n | Effective power in historical Schulze–Hardy trend (often quoted ~6 for negative arsenic sulphide sol) |
| z | Charge number of the ion (counter-ion to the colloid) that causes coagulation |
When to use this
Lyophobic sols coagulated by electrolytes: the ion whose charge is opposite to the colloid is effective; higher |z|, much smaller concentration needed. Exact exponent is system-dependent; JEE tests the qualitative law and comparative ordering.