Oquizy

An aqueous solution of potassium nitrate is electrolysed using inert platinum electrodes. What are the products at the electrodes?

Hydrogen and nitrogen Hydrogen and oxygen Potassium and nitrogen Potassium and oxygen

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

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

What is the correct half-equation at the anode?

H⁺ + e⁻ → ½H₂ H₂ → 2H⁺ + 2e⁻ H₂O → ½O₂ + 2H⁺ + 2e⁻ O₂ + 4e⁻ → 2O²⁻

An aqueous solution of sodium chloride is electrolysed using carbon electrodes. When the solution is dilute, gas X forms at the anode. When it is concentrated, gas Y is released instead.What are gases X and Y?

X: Cl₂, Y: O₂ X: H₂, Y: Cl₂ X: O₂, Y: Cl₂ X: O₂, Y: H₂

Quiz: Chemistry - Redox Chemistry