Question

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

• A. a thin layer of $Ag$ is formed on $Cu$
• B. more voltage is required
• C. $A{g}^{+}$ ions are completely removed from solution
• D. less availability of $A{g}^{+}$ ions, as Cu can not displace Ag from $\left[Ag\right(CN{)}_2$]${}^{-}$ ion

Answer 1

Answer: (D)

The rate of dissociation is high in the case of silver nitrate as it is ionic molecule whereas Potassium argentocyanide is the complex molecule. During the dissociation of potassium argentocyanide the rate gets slow down as the silver is present inside the complex and it is difficult to displace it from that complex by Cu.