Electrochemistry MCQs FPSC Chemistry

Electrochemistry MCQs

1. In the reaction Cl₂ → 2Cl⁻, chlorine is:
a) Oxidized
b) Reduced
c) Neither
d) Both
Answer: b) Reduced

2. The mnemonic “LEO GER” refers to:
a) Losing Electrons Oxidation, Gaining Electrons Reduction
b) Gaining Electrons Oxidation, Losing Electrons Reduction
c) Losing Energy Oxidation, Gaining Energy Reduction
d) None of these
Answer: a) Losing Electrons Oxidation, Gaining Electrons Reduction

3. In the reaction Na → Na⁺, sodium acts as a:
a) Reducing agent
b) Oxidizing agent
c) Catalyst
d) Spectator ion
Answer: a) Reducing agent

4. The oxidizing agent in a redox reaction is:
a) Reduced
b) Oxidized
c) Neither
d) Both
Answer: a) Reduced

5. Which substance is oxidized in Fe + CuSO₄ → FeSO₄ + Cu?
a) Fe
b) Cu²⁺
c) SO₄²⁻
d) None
Answer: a) Fe

6. In the reaction 2H₂ + O₂ → 2H₂O, oxygen is:
a) Oxidized
b) Reduced
c) A reducing agent
d) Neutral
Answer: b) Reduced

7. Which statement is true for all redox reactions?
a) Oxygen is involved
b) Electrons are transferred
c) Protons are transferred
d) Heat is released
Answer: b) Electrons are transferred

8. In the reaction MnO₄⁻ → Mn²⁺, manganese is:
a) Oxidized
b) Reduced
c) Unchanged
d) A catalyst
Answer: b) Reduced

9. The reducing agent in Zn + Cu²⁺ → Zn²⁺ + Cu is:
a) Zn
b) Cu²⁺
c) Zn²⁺
d) Cu
Answer: a) Zn

10. In SO₃²⁻ → SO₄²⁻, sulfur undergoes:
a) Oxidation
b) Reduction
c) No change
d) Disproportionation
Answer: a) Oxidation


Electrolysis

11. During molten NaCl electrolysis, the product at the anode is:
a) Na
b) Cl₂
c) H₂
d) O₂
Answer: b) Cl₂

12. In aqueous KI electrolysis, the cathode product is:
a) K
b) I₂
c) H₂
d) O₂
Answer: c) H₂

13. Electrolysis of water produces:
a) H₂ and O₂
b) H₂O and O₃
c) H⁺ and OH⁻
d) None
Answer: a) H₂ and O₂

14. The anode in an electrolytic cell is:
a) Positive
b) Negative
c) Neutral
d) None
Answer: a) Positive

15. The purpose of a salt bridge is to:
a) Transfer electrons
b) Maintain electrical neutrality
c) Increase voltage
d) Reduce resistance
Answer: b) Maintain electrical neutrality

16. In electroplating, the object to be plated is placed at the:
a) Anode
b) Cathode
c) Salt bridge
d) Electrolyte
Answer: b) Cathode

17. Faraday’s first law relates mass deposited to:
a) Current and time
b) Voltage and resistance
c) Temperature and pressure
d) None
Answer: a) Current and time

18. To plate 1 mole of Ag from AgNO₃, the required charge is:
a) 1 F
b) 2 F
c) 3 F
d) 0.5 F
Answer: a) 1 F

19. A current of 5A flows for 2 hours. Total charge (in C) is:
a) 36,000
b) 7,200
c) 10,000
d) 3,600
Answer: a) 36,000

20. Electrolysis is used in:
a) Metal refining
b) Electroplating
c) Both
d) None
Answer: c) Both


Galvanic/Voltaic Cells

21. In a galvanic cell, electrons flow from:
a) Anode to cathode
b) Cathode to anode
c) Salt bridge to anode
d) None
Answer: a) Anode to cathode

22. The cathode in a galvanic cell is the site of:
a) Oxidation
b) Reduction
c) Neutralization
d) Hydrolysis
Answer: b) Reduction

23. The standard hydrogen electrode (SHE) has a potential of:
a) 0.00 V
b) 1.00 V
c) -1.00 V
d) 2.00 V
Answer: a) 0.00 V

24. In a Daniell cell, the anode is made of:
a) Zn
b) Cu
c) Pt
d) Ag
Answer: a) Zn

25. If E°cell > 0, the reaction is:
a) Spontaneous
b) Non-spontaneous
c) At equilibrium
d) None
Answer: a) Spontaneous

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