Question

When a dilute \(AgNO_3\) solution is mixed with excess of dilute \(KI\), the colloidal solution formed is

• A. \(AgNO_3/I^-\)
• B. \(AgI\)
• C. \(AgI/Ag^+\)
• D. \(AgI/I^-\)

Hint:

In precipitate sols, the ion present in excess is preferentially adsorbed on the colloidal particles and determines the charge on the sol.

Answer 1

The Correct Option is D

Step 1: Apply preferential adsorption principle.
AgNO₃ + KI(excess) → AgI↓ + KNO₃. With excess KI, I⁻ ions remain after precipitation and adsorb onto the AgI particle surfaces, imparting a negative charge to the colloid.

Step 2: Final Answer:
The sol is represented as AgI/I⁻ (option 4).