Oquizy

John tries electroplating. He uses a copper spoon as the cathode, and a pure copper rod as the anode in copper(II) sulfate solution. After 30 minutes, the mass of the spoon increases by 2.4 g. What happens at the anode?

Anode dissolves completely Mass decreases by 2.4 g Mass increases by 2.4 g No change in mass

Xinyi filled a beaker with aqueous CuSO₄ for electrolysis and she used inert carbon electrodes. She labels the cathode A and the anode B.
- She observed the following: Bubbles forming at electrode B.
- Red-brown solid forming on electrode A.
Which option correctly identifies the reactions at the electrodes?

A: 2H⁺ + 2e⁻ → H₂; B: Cl⁻ → Cl₂ + e⁻ A: Cu → Cu²⁺ + 2e⁻; B: 4OH⁻ → O₂ + 2H₂O + 4e⁻ A: Cu²⁺ + 2e⁻ → Cu; B: 4OH⁻ → O₂ + 2H₂O + 4e⁻ A: Cu²⁺ → Cu + 2e⁻; B: 2OH⁻ + 2e⁻ → H₂O

Which ionic half-equation shows oxidation?

2H⁺ + 2e⁻ → H₂ Cl₂ + 2e⁻ → 2Cl⁻ Cu²⁺ + 2e⁻ → Cu Zn → Zn²⁺ + 2e⁻

What is oxidation in terms of electron transfer?

Gain of electrons Gain of protons Loss of electrons Loss of neutrons

What is the oxidation state of sulfur in H₂SO₄?

+2 +4 +6 -2

What happens to the mass of the cathode during copper electroplating?

Decreases Increases Stays the same Turns green

Quiz: Chemistry - Redox Chemistry