Half-equations and balancing redox equations Quiz
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5 questions, one answer each
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1. Which is a reduction half-equation?
- A. Fe²⁺ → Fe³⁺ + e⁻
- B. 2I⁻ → I₂ + 2e⁻
- C. Cu²⁺ + 2e⁻ → Cu
- D. Zn → Zn²⁺ + 2e⁻
2. How many electrons are needed to balance MnO₄⁻ + 8H⁺ + ?e⁻ → Mn²⁺ + 4H₂O?
- A. 3
- B. 7
- C. 2
- D. 5
3. MnO₄⁻ + 8H⁺ + 5Fe²⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O. What amount of Fe²⁺ reacts with 2.0 × 10⁻³ mol of MnO₄⁻?
- A. 1.0 × 10⁻² mol
- B. 4.0 × 10⁻⁴ mol
- C. 2.0 × 10⁻³ mol
- D. 1.0 × 10⁻³ mol
4. Cl₂ + 2e⁻ → 2Cl⁻. What does this show?
- A. Chlorine is oxidised
- B. Chlorine is reduced
- C. Chloride is reduced
- D. Electrons are lost
5. In balancing 2 half-equations, why are they multiplied?
- A. To balance the oxygen
- B. To balance the hydrogen ions
- C. So that the electrons lost equal the electrons gained
- D. To get 1 mole of each product