Question

On which of the following properties does the coagulating power of an ion depend?

Options

• Both magnitude and sign of the charge on the ion.

• Size of the ion alone.

• The magnitude of the charge on the ion alone.

• The sign of charge on the ion alone.

Answer 1

Both magnitude and sign of the charge on the ion.

Explanation:

According to the Hardy-Schulze rule, the oppositely charged ion to the colloidal particle causes coagulation, and ions with higher charge magnitude have greater coagulating power. Thus, both the charge sign (to be oppositely charged) and the magnitude affect coagulation.

For example, positively charged sols coagulate due to negatively charged ions and vice versa, with higher valency ions being more effective (e.g., Al³⁺ > Ba²⁺ > Na⁺ for negatively charged sols).