A student wanted to electroplate a spoon with silver. He tried four different set-ups to electroplate the spoon as depicted in the diagrams given below.
Answer the following questions based on the above diagrams:
(a) Identify the set-up made by the student which would result in the uniform and smooth electroplating of the spoon with silver.
(b) In which set up will the coating on the spoon be uneven?
(c) Write the reaction taking place at the anode for the correct set-up.
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(a) Set-up Q — It uses sodium argentocyanide as the electrolyte, which releases silver ions slowly and gives a uniform, smooth and adherent coating of silver on the spoon (cathode).
(b) Set-up P — It uses silver nitrate solution, which ionises readily and releases a high concentration of silver ions, so silver is deposited too quickly, giving an uneven and rough coating.
(c) At the anode, the silver plate dissolves into the electrolyte:
Ag - e- ⟶ Ag+