Question

The electrolyte used for electroplating an article with silver is:

• A. Silver nitrate solution
• B. Silver cyanide solution
• C. Sodium argentocyanide solution
• D. nickel sulphate solution

Answer 1

The correct option is C

Sodium argentocyanide solution

Explanation for the correct option:

(C) Sodium argentocyanide solution

• Electroplating is the process of covering metal with another metal by electrolysis.
• Sodium argentocyanide is a complex salt that does not completely dissociate into ions.
• In the Electroplating of an article with silver, an aqueous solution of sodium argentocyanide is used as an electrolyte. In this solution, silver ions $\left({\mathrm{Ag}}^{+}\right)$ migrates slowly due to the complex nature of sodium argentocyanide and the deposition of silver on an article is smooth and uniform.

$$\begin{gathered} \mathrm{Na}\left[\mathrm{Ag}{\left(\mathrm{CN}\right)}_2\right]\left(\mathrm{aq}\right)\to {\mathrm{Na}}^{+}\left(\mathrm{aq}\right)+{\mathrm{Ag}}^{+}\left(\mathrm{aq}\right)+2{\mathrm{CN}}^{-}\left(\mathrm{aq}\right) \\ \mathrm{sodium}\mathrm{argentocyanide}\mathrm{cations}\mathrm{anion} \end{gathered}$$

Explanation for the incorrect option:

(A) Silver nitrate solution is not used for electroplating an article with silver because the process is very fast and the deposition of silver on an article is not uniform.

(B) Silver cyanide solution is not used for electroplating an article with silver due to the faster rate of reaction and non-uniform deposition.

(D) nickel sulphate solution provides nickel metal for electroplating.

Hence, The electrolyte used for electroplating an article with silver is Sodium argentocyanide solution.