Electroplating setup for copper deposition

Steps:

• Identify the goal: deposit copper ions onto steel key via reduction at cathode.
• Select electrolyte with copper ions: aqueous copper(II) sulfate provides Cu²⁺.
• Choose anode: pure copper dissolves to replenish Cu²⁺ ions.
• Assign electrodes: steel key as cathode (negative) for deposition; copper as anode (positive).

Why A is correct:

• Steel key as negative electrode (cathode) allows Cu²⁺ reduction (Cu²⁺ + 2e⁻ → Cu) to plate copper onto it.

Why the others are wrong:

• B: Lacks electrode polarity; steel key not specified as cathode, preventing controlled deposition.
• C: Dilute sulfuric acid has no Cu²⁺ ions, so no copper plating occurs.
• D: Dilute sulfuric acid lacks Cu²⁺; pure copper as cathode would deposit nothing useful on steel key.

Final answer: A