Question

Peptization of silver iodide can take place on addition of:
A. Silver nitrate
B. Potassium iodide
C. Potassium nitrate
D. Potassium chloride

Answer 1

Peptization is the process liable for the formation of stable scattering of colloidal particles in the scattering medium. As such, it might be characterized as a process of changing over a precipitate into a colloidal sol by shaking it with a scattering medium within the sight of a small quantity of electrolyte.

Complete step by step solution:
The cause of Peptization- As electrolyte is added to a newly precipitated substance, the particles of the precipitate specially adsorbs one specific sort of particles of the electrolyte. Accordingly they get dispersed because of electrostatic repulsions. This gives the particles of colloidal size.
A precipitate of silver iodide $AgI$ can be peptized by shaking with a dilute solution of silver nitrate or$KI$.
When peptized by $KI$ solution, a positively charged sol is generated because of adsorption of ${{I}^{-1}}$ from $KI$. When peptized by $AgN{{O}_{3}}$ solution, positively charged sol is framed because of adsorption of normal $A{{g}^{+}}$ from $AgN{{O}_{3}}$.
The changes in the level of dispersion of $AgI$ hydrosols created by reaction of $AgN{{O}_{3}}$ and $KI$ with the addition of different electrolytes (1–60 min after expansion of $AgN{{O}_{3}}$ to $KI$) were examined by photometric methods. The outcomes acquired propose that during the process of rapid condensation (caused by a unexpected increment in concentration to a value higher than the critical one) colloidal particles don't frame by continuous growth of individual nuclei yet through disaggregation of free and amorphous that is thermodynamically insecure bunches of recently shaped structures.
This question has multiple correct answers.

Hence, the correct option is A and B .

Note: When silver nitrate solution is added to a slight excess of potassium iodide solution, the precipitated silver iodide adsorbs iodide ions (present in excess) from the dispersion medium and negatively charged colloidal solution results.