Electroplating setup requires metal ion electrolyte, plating metal as anode, and object as cathode

Steps:

• Identify cathode as object to plate (steel key receives copper).
• Identify anode as source of plating metal (pure copper dissolves to release Cu²⁺ ions).
• Select electrolyte with metal ions (aqueous copper(II) sulfate provides Cu²⁺).
• Arrange as electrolyte, anode (copper), cathode (steel key).

Why A is correct:

• Follows Faraday's laws of electrolysis: Cu²⁺ ions from CuSO₄ solution reduce at cathode (steel key) to deposit Cu, while anode (copper) oxidizes to replenish ions.

Why the others are wrong:

• B: Reverses electrodes; steel anode dissolves, plating iron onto copper cathode instead.
• C: Sulfuric acid lacks Cu²⁺ ions, so no copper deposition occurs.
• D: Sulfuric acid lacks Cu²⁺ ions, and reversed electrodes cause steel dissolution without copper plating.

Final answer: A