Question

The electrolytes usually used in the electroplating of gold and silver, respectively are:
A.${[Au{(OH)_4}]^ - }\& {[Ag{(OH)_2}]^ - }$
B.${[Au{(CN)_2}]^ - }\& {[AgC{l_2}]^ - }$
C.${[Au{(N{H_3})_2}]^ + }\& {[Ag{(CN)_2}]^ - }$
D.${[Au{(CN)_2}]^ - }\& {[Ag{(CN)_2}]^ - }$

Answer 1

Hint: Basically, electroplating is the process of plating a metal onto the other by hydrolysis to prevent corrosion of metal and also for decaying purposes. this process uses an electric current to reduce the dissolved metal cations in order to develop a lean coherent metal coating on the electrode.

Complete step-by-step answer: So, before we start the solution, I have to tell you that the noble metals are only used in the process of electroplating.
We know that the electroplating process uses an anode and a cathode. The metal dissolved from the anode can be plated onto the cathode.
The electrolytes that we use in electroplating gold and silver are ${[Au{(CN)_2}]^ - }\& {[Ag{(CN)_2}]^ - }$
For electroplating silver metal, the anode is a bar of silver metal and the electrolytes is a solution of silver cyanide in water and for electroplating gold the anode is a gold anode and the electrolyte is of gold cyanide.
The solution used in the electroplating of gold and silver is $Na[Au{(CN)_2}]$ (Sodium auro-cyanide) and $Na[Ag{(CN)_2}]$ (Sodium argento cyanide).
In the process of gold $Au(s)$ plating the article to be plated out acts as a cathode and the pure metal block acts as an anode by which electroplating will be done and the $Na[Au{(CN)_2}]$ (Sodium auro-cyanide) solution is used in this process
In the process of silver $Ag(s)$plating the article to be plated out acts as a cathode and the pure metal block acts as an anode by which electroplating will be done and the $Na[Ag{(CN)_2}]$ (Sodium argento cyanide) solution is used in this process.

Therefore, the correct answer is Option D.

Note:Don’t get confused between Option B and Option D. Both the electrolytes will be of cyanide. Also, cyanide is used in electroplating gold and silver because it prevents precipitation of silver cyanide and gold cyanide salt from the solution and provides electrical conductivity of the electrolyte and helps dissolution of silver and gold anodes.