Electrolytic Refining of Impure Copper

Steps:

• Set up electrolysis with impure copper as anode, pure copper as cathode, and copper(II) sulfate electrolyte.
• Apply current: anode oxidizes, releasing Cu²⁺ ions into solution; impurities form sludge.
• Cu²⁺ ions migrate to cathode and reduce to deposit pure copper.
• Monitor electrolyte color change to assess process completion.

Why B is correct:

• Cu²⁺ ions from anode dissolution deposit on cathode, reducing electrolyte concentration per Faraday's laws of electrolysis, fading the blue color.

Why the others are wrong:

• A: Impure copper anode is used to dissolve and purify, not pure.
• C: Duplicate of B; not a distinct option.
• D: Electrolyte is copper(II) sulfate in dilute sulfuric acid, as copper oxide is insoluble in water.

Final answer: B