Question

The sol given below with negatively charged colloidal particles is :

• A. $A{l}_2{O}_3.x{H}_{2}O\text{in water}$
• B. $FeC{l}_3\text{added to hot water}$
• C. $AgN{O}_3\text{added to}KI\text{solution}$
• D. $KI\text{added to}AgN{O}_3\text{solution}$

Answer 1

The correct option is C $AgN{O}_3\text{added to}KI\text{solution}$

When $AgN{O}_3$ solution is added to $KI$ solution
$AgN{O}_3\left(aq\right)+KI\left(aq\right)\to AgI\left(s\right)\downarrow +AgN{O}_3\left(aq\right)$
$AgI$ gets precipitated.
The precipitated silver iodide adsorbs iodide ions $\left(I^{-}\right)$ from the dispersion medium and negatively charged colloidal sol is formed $AgI/I^{-}$

When $KI$ solution is added to $AgN{O}_3$ solution
$AgN{O}_3\left(aq\right)+KI\left(aq\right)\to AgI\left(s\right)\downarrow +AgN{O}_3\left(aq\right)$
$AgI$ gets precipitated.

The precipitated silver iodide adsorbs $A{g}^{+}$ions from the dispersion medium and positively charged colloidal sol is formed $AgI/A{g}^{+}$
Option (b) is correct