Paper 2 Electrochemistry MCQ Practice
10 multiple-choice questions on electrochemistry for IGCSE Chemistry Paper 2. Covers electrolysis, electrodes, electroplating, and fuel cells.
Published by IGCSEChemistry.com.my
Chemistry teaching team: K. S. Tan (15+ years teaching IGCSE Chemistry) and Ms Yash (10+ years teaching IGCSE Chemistry) and Ms Kartini (15+ years teaching IGCSE Chemistry).
Mapped to Cambridge IGCSE Chemistry 0620 (2026–2028). Last updated 2026-08-19.
Ten multiple-choice questions in the style of IGCSE Chemistry Paper 2. Choose the best answer for each, then check the mark scheme.
Question 1
During electrolysis, positive ions move towards the:
A. anode B. cathode C. electrolyte D. power supply
Answer
B
Positive ions (cations) are attracted to the negative electrode (cathode) during electrolysis. The cathode is connected to the negative terminal of the power supply. Negative ions (anions) move to the positive electrode (anode). Remember: Cations go to the Cathode.
Question 2
What is an electrolyte?
A. A solid metal that conducts electricity B. An ionic compound that conducts electricity when molten or in aqueous solution C. Any liquid that conducts electricity D. A substance that produces electrons
Answer
B
An electrolyte is an ionic compound that conducts electricity when molten or dissolved in water because its ions are free to move and carry charge. In the solid state, the ions are fixed in a lattice and cannot conduct. Examples include molten lead(II) bromide and aqueous copper(II) sulfate solution.
Question 3
What are the products at the electrodes when molten lead(II) bromide is electrolysed?
| Cathode | Anode | |
|---|---|---|
| A | Bromine | Lead |
| B | Lead | Bromine |
| C | Hydrogen | Oxygen |
| D | Lead | Oxygen |
Answer
B
In the electrolysis of a molten binary compound, the metal is deposited at the cathode and the non-metal is produced at the anode. Lead (Pb²⁺) ions gain electrons at the cathode to form lead metal. Bromide (Br⁻) ions lose electrons at the anode to form bromine gas.
Question 4
During electroplating, the object to be plated is used as:
A. the anode B. the cathode C. the electrolyte D. the power supply
Answer
B
The object to be plated is the cathode (negative electrode). Metal ions from the electrolyte solution are attracted to the cathode, where they gain electrons and are deposited as a thin layer of metal on the object. The anode is usually made of the plating metal, which dissolves to replace the ions in solution.
Question 5
Concentrated aqueous sodium chloride solution is electrolysed. What gas is produced at the anode?
A. Hydrogen B. Oxygen C. Chlorine D. Sodium vapour
Answer
C
When concentrated sodium chloride solution is electrolysed, chloride ions (Cl⁻) are discharged at the anode in preference to hydroxide ions because of their high concentration. Chlorine gas (Cl₂) is produced. At the cathode, hydrogen gas is produced (not sodium, because sodium is too reactive).
Question 6
In a hydrogen-oxygen fuel cell, the overall reaction is:
A. 2H₂ + O₂ → 2H₂O B. H₂O → H₂ + O₂ C. 2H₂O → 2H₂ + O₂ D. CH₄ + 2O₂ → CO₂ + 2H₂O
Answer
A
A hydrogen-oxygen fuel cell combines hydrogen and oxygen to produce water and electrical energy. The reaction 2H₂ + O₂ → 2H₂O is exothermic. The only product is water, making fuel cells a clean source of energy with no carbon dioxide emissions.
Question 7
What type of current must be used for electrolysis?
A. Alternating current (a.c.) B. Direct current (d.c.) C. Either a.c. or d.c. D. No current is needed
Answer
B
Direct current (d.c.) must be used for electrolysis. D.c. ensures that one electrode is always positive (anode) and the other is always negative (cathode), so ions consistently move in one direction. With alternating current, the polarity switches constantly and no net electrolysis occurs.
Question 8
During the electrolysis of dilute sulfuric acid, what is produced at the cathode?
A. Sulfur B. Oxygen C. Hydrogen D. Sulfur dioxide
Answer
C
In the electrolysis of dilute sulfuric acid, hydrogen ions (H⁺) are discharged at the cathode: 2H⁺ + 2e⁻ → H₂. At the anode, hydroxide ions are discharged to form oxygen and water: 4OH⁻ → O₂ + 2H₂O + 4e⁻. The volume of hydrogen collected is twice the volume of oxygen.
Question 9
Which statement about a hydrogen fuel cell is correct?
A. It produces carbon dioxide and water. B. It converts chemical energy directly into electrical energy. C. It is an example of electrolysis. D. Hydrogen is produced as a waste product.
Answer
B
A fuel cell converts chemical energy directly into electrical energy without combustion. The only product is water, so there is no carbon dioxide. It is not electrolysis (electrolysis uses electrical energy to drive a chemical reaction; a fuel cell does the reverse). Hydrogen is the fuel, not a product.
Question 10
In the electrolysis of aqueous copper(II) sulfate with carbon electrodes, copper is deposited at the cathode. Why is copper discharged instead of hydrogen?
A. Copper is more reactive than hydrogen. B. Copper is less reactive than hydrogen. C. There are more copper ions than hydrogen ions. D. Copper ions are larger than hydrogen ions.
Answer
B
At the cathode, the less reactive metal ion is preferentially discharged. Copper is below hydrogen in the reactivity series, so Cu²⁺ ions gain electrons in preference to H⁺ ions. Cu²⁺ + 2e⁻ → Cu. If the metal is above hydrogen in the reactivity series (e.g. sodium), hydrogen would be produced instead.
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