Anode mass decreases linearly due to copper dissolution

Steps:

• In electrolysis of CuSO₄(aq) with Cu electrodes, anode reaction is Cu → Cu²⁺ + 2e⁻, dissolving copper.
• Cathode reaction is Cu²⁺ + 2e⁻ → Cu, depositing copper.
• Constant current means constant rate of electron flow, so anode loses mass at constant rate.
• Mass loss follows Faraday's first law: mass ∝ charge passed (It), linear with time t.

Why C is correct:

• C shows linear decrease in anode mass vs. time, as Faraday's law predicts constant dissolution rate for constant current.

Why the others are wrong:

• A: Horizontal line implies constant mass, but anode dissolves.
• B: Increasing mass contradicts anode loss.
• D: Curved line suggests varying rate, but current is constant.

Final answer: C