Question

One desires to prepare a positively charged sol of silver iodide. This can be achieved by

• A. adding small amount of $AgNO_3$ solution to KI solution in slight excess
• B. adding small amount of KI solution to $AgNO_3$ solution in slight excess
• C. mixing equal volumes of equimolar solutions of $AgNO_3$ and KI
• D. None of these

Answer 1

Answer: (B)

$KI+ AgNO_3 $ (slight excess) $ \rightarrow AgI + KNO_3$
$ AgNO_3 \rightarrow Ag^{+} + NO_3^{-} $
$ AgI(s) + Ag^{+} \xrightarrow [AgI] Ag^{+}$