Discussion Forum



1)

In the silver plating of copper, K[Ag(CN)2] is used instead ofAgNO3. The reason is


A) a thin layer of Ag is formed on Cu

B) more voltage is required

C) Ag+ ions are completely removed from solution

D) less availability of $Ag^{+}$ions, as Cu cannot displace Ag from $[Ag(CN)_{2}]^{-} ion$

Answer:

Option D

Explanation:

In the silver plating of copper, K[Ag(CN)2]  is used instead of AgNO3. Copper being more electropositive readily precipitate silver from their salt solution

Cu + 2AgNO3 → Cu(NO3)2 + Ag

whereas in [Ag(CN)2] solution a complex anion K[Ag(CN)2]- is formed and hence Ag+ are less available in the solution and therefore copper cannot displace Ag from its complexion