Question

If a dilute solution of\( \mathrm{AgNO_3}\) is added to a dilute solution of excess \(\mathrm{NaI}\), then the species adsorbed on AgI colloidal particles is
 

• A. \(\mathrm{NO_3^-}\)
• B. \(\mathrm{Na^+}\)
• C. \(\mathrm{I^-}\)
• D. \(\mathrm{Ag^+}\)

Hint:

The charge on a colloidal particle depends on the ion preferentially adsorbed from the dispersion medium.

Answer 1

The Correct Option is C

Step 1: Identify the colloidal system formed.
When \(\mathrm{AgNO_3}\) is added to excess \(\mathrm{NaI}\), silver iodide (\(\mathrm{AgI}\)) sol is formed.
Step 2: Apply the rule of preferential adsorption.
In a colloidal solution, the ion present in excess is preferentially adsorbed on the surface of colloidal particles.
Step 3: Determine the adsorbed ion.
Since \(\mathrm{NaI}\) is present in excess, iodide ions \(\mathrm{I^-}\) are adsorbed on AgI particles, giving them a negative charge.
Step 4: Conclusion.
Thus, the species adsorbed on AgI colloidal particles is \(\mathrm{I^-}\).