In the silver plating of copper, $\mathrm{K}\left[\mathrm{Ag}(\mathrm{CN})_2\right]$ is used instead of $\mathrm{AgNO}_3$. The reason is

Question

In the silver plating of copper, $\mathrm{K}\left[\mathrm{Ag}(\mathrm{CN})_2\right]$ is used instead of $\mathrm{AgNO}_3$. The reason is, A thin layer of $\mathrm{Ag}$ is formed on $\mathrm{Cu}$, More voltage is required, $\mathrm{Ag}^{+}$ions are completely removed from solution, Less availability of $\mathrm{Ag}^{+}$ions, as Cu cannot displace $\mathrm{Ag}$ from $\left[\mathrm{Ag}(\mathrm{CN})_2\right]^{-}$ion

MARKS App · Accepted Answer

In the silver plating of copper, $\mathrm{K}\left[\mathrm{Ag}(\mathrm{CN})_2\right]$ is used instead of $\mathrm{AgNO}_3$. Copper being more electropositive readily precipitate silver from their salt solution $\mathrm{Cu}+2 \mathrm{AgNO}_3 \longrightarrow \mathrm{Cu}\left(\mathrm{NO}_3\right)_2+\mathrm{Ag}$ whereas in $\mathrm{K}\left[\mathrm{Ag}(\mathrm{CN})_2\right]$ solution a complex anion $\left[\mathrm{Ag}(\mathrm{CN})_2\right]^{-}$is formed and hence $\mathrm{Ag}^{+}$are less available in the solution and therefore copper cannot displace $\mathrm{Ag}$ from its complex ion.

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