Q.What modification can you suggest in the Hardy Schulze law?

Hardy–Schulze law states that the ion carrying charge opposite to that of the sol causes coagulation, and its coagulating power increases with the magnitude of its charge. A useful modification is to also consider ion size. …

Step 1 – State Hardy–Schulze law. The coagulation of a sol is brought about by the ion carrying a charge opposite to that of the colloidal particles, and its coagulating (flocculating) power increases with the magnitude (valency) of the charge. For example, to coagulate a negative $As_2S_3$ sol: $Al^{3+} > Ba^{2+} > Na^{+}$.

Step 2 – The limitation. The law is framed only in terms of the sign and magnitude of the charge; it does not account for differences between ions of the same charge. …

State the original Hardy–Schulze law (charge sign + valency of the opposite ion), identify that it ignores ion siz …

• Restating the law unchanged instead of modifying it.
• Saying the ion of the same charge as the sol coagulates it — it must be the oppositely charged ion. …