On which of the following properties does the coagulating power of an ion depend?
- The magnitude of the charge on the ion alone
- Size of the ion alone
- Both magnitude and sign of the charge on the ion
- The sign of charge on the ion alone
Answer
(3) Both magnitude and sign of the charge on the ion
Solution
As per NCERT (Hardy–Schulze rule):
(i) The ion carrying charge opposite to that of the sol particles neutralises them and causes coagulation ⇒ the sign of the charge matters.
(ii) The greater the valence of the flocculating ion, the greater its power to cause coagulation ⇒ the magnitude of the charge matters.
∴ Coagulating power depends on both the magnitude and the sign of the charge on the ion.
Answer: (3)