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Question: Answered & Verified by Expert
In the silver plating of copper, $\mathrm{K}\left[\mathrm{Ag}\left(\mathrm{CN}_2\right]\right.$ is used instead of $\mathrm{AgNO}_3$. The reason is:
ChemistryCoordination CompoundsNEETNEET 2002
Options:
  • A a thin layer of $\mathrm{Ag}$ is formed on $\mathrm{Cu}$
  • B more voltage is required
  • C $\mathrm{Ag}^{+}$ions are completely removed from solution
  • D less availability of $\mathrm{Ag}^{+}$ions, as $\mathrm{Cu}$ cannot displace $\mathrm{Ag}$ from $\left[\mathrm{Ag}\left(\mathrm{CN}_2\right]^{-}\right.$ ion
Solution:
2816 Upvotes Verified Answer
The correct answer is: less availability of $\mathrm{Ag}^{+}$ions, as $\mathrm{Cu}$ cannot displace $\mathrm{Ag}$ from $\left[\mathrm{Ag}\left(\mathrm{CN}_2\right]^{-}\right.$ ion
Copper being more electropositive readily precipitate silver from their salt \(\left(\mathrm{Ag}^{+}\right)\) solution.
\(\mathrm{Cu}+2 \mathrm{AgNO}_3 \rightarrow \mathrm{Cu}\left(\mathrm{NO}_3\right)_2+\mathrm{Ag}\)
In \(\mathrm{K}\left[\mathrm{Ag}(\mathrm{CN})_2\right]\) solution a complex anion \(\left[\mathrm{Ag}(\mathrm{CN})_2\right]\) is formed so \(\mathrm{Ag}^{+}\) ions are less available in the solution and Cu cannot displace Ag from this complex ion.

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