Which of the following is used in electro-plating process ?

• 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.

$\mathrm{Na}\left[\mathrm{Ag} {\left(\mathrm{CN}\right)}_2\right] \to {\mathrm{Ag}}^{+ }+{\mathrm{Na}}^{+}+2{\mathrm{CN}}^{-}$

sodium argentocyanide         cations       anoins