Question
A colloidal solution of Agl is prepared by two different methods shown below:
(i) What is the charge of AgI colloidal particles in the two test tube (A) and (B).
(ii) Give reason for the origin of change.
Solution
Answer:
When silver nitrate solution is added to potassium iodide solution, negatively charged sol of AgI is formed this due to selective adsorption of I- ion from the dispersion medium.
AgI + I- ---> [AgI]I-
On other hand when KI is added to AgNO3 solution a positively charged sol of AgI is formed this is due to slective adsorption of Ag+ ion present in the dispersion medium.
AgI + Ag+ ---> [AgI]Ag+.
