Question

When an excess of a very dilute aqueous solutions of KI is added to a very dilute aqueous solutions of silver nitrate, the colloidal particles of silver iodide are associated with which of the following Helmholtz double layer?

• A.
• B. $\mathrm { AgI } / \mathrm { K } ^ { + } : \mathrm { NO } _ { 3 } ^ { - }$
• C.
• D.

Answer 1

Answer: (D)

Answer 2

As excess of KI has been added, $\mathrm { I } ^ { - }$ ions are adsorbed on Agl forming a fixed (and giving it a negative charge).It then attracts the counter ions $\left( \mathrm { K } ^ { + } \right)$form the medium forming a second layer (diffused layer).