CIE iGCSE Co-Ordinated Science C4.1 Electrolysis Exam Style Questions Paper 1
Question
Apparatus used for electrolysis is shown. Which label identifies the electrolyte?
▶️Answer/Explanation
Answer: D
Explanation: The electrolyte is the substance that undergoes electrolysis, typically a molten or aqueous ionic compound, and is labeled as D in the diagram.
Question
The diagram shows the electrolysis of a compound.
When the switch is closed, the solution around electrode P turns orange because a halogen is formed.
The positive electrode P is called the ……1……, and the halogen is ……2…… .
Which words complete gaps 1 and 2?
A anode / bromine
B anode / chlorine
C cathode / bromine
D cathode / chlorine
▶Answer/Explanation
Answer: A
Explanation: The positive electrode is the anode, and the orange color indicates the formation of bromine, which is a halogen.
Question
The diagram shows the electrolysis of dilute sulfuric acid.
Gas G ignites with a ‘pop’ when it is tested with a lighted splint.
What is gas G and at which electrode is it formed?
▶️Answer/Explanation
Ans :B
Question
The diagram shows the electrolysis of dilute sulfuric acid using inert electrodes.
Which row shows the products formed at each electrode and describes the bonding in sulfuric acid?
▶️Answer/Explanation
Ans :A
Question
Which process is used to produce sodium and chlorine from the compound sodium chloride?
(A) chromatography
(B) cracking
(C) distillation
(D) electrolysis
▶️Answer/Explanation
Ans: D
Question
Which process is used to produce sodium and chlorine from the compound sodium chloride?
(A) chromatography
(B) cracking
(C) distillation
(D) electrolysis
▶️Answer/Explanation
Ans: D
Question
Which process is used to produce sodium and chlorine from the compound sodium chloride?
(A) chromatography
(B) cracking
(C) distillation
(D) electrolysis
▶️Answer/Explanation
Ans : D
Question
Dilute sulfuric acid is electrolysed using the apparatus shown.
Which product forms at the cathode?
A hydrogen
B oxygen
C sulfur dioxide
D water vapour
▶️Answer/Explanation
Ans : A
Question
Molten lead(II) bromide is electrolysed using inert electrodes as shown.
An element is produced at the negative electrode.
What is the name of the element and of the negative electrode?
▶️Answer/Explanation
Ans : D
Question
Which diagram shows equipment used to electroplate nickel with copper?
▶️Answer/Explanation
Ans : D
Question
The apparatus used for the electrolysis of copper chloride is shown.
Which words complete labels 1, 2 and 3?
▶️Answer/Explanation
Ans: A
Question
Which substance does not undergo electrolysis?
(A) aqueous copper chloride
(B) copper wire
(C) dilute sulfuric acid
(D) molten lead(II) bromide
▶️Answer/Explanation
Ans: B
Question
The diagram shows the electrolysis of dilute sulfuric acid using inert electrodes.
Which substance is produced by electrolysis at the negative electrode?
(A) hydrogen
(B) oxygen
(C) sulfur dioxide
(D) water vapour
▶️Answer/Explanation
Ans : A
Question
Concentrated aqueous sodium chloride is electrolysed using inert electrodes.
Which row describes observations of the tests on the gases collected at the electrodes?
▶Answer/Explanation
Ans : C
Question
Which elements are formed at the electrodes during the electrolysis of concentrated aqueous
sodium chloride?
▶️Answer/Explanation
Ans: B
Question
Molten lead(II) bromide is electrolysed.
Which equation represents the reaction at the cathode?
A. 2Br⁻ → Br₂ + 2e⁻
B. Br₂ + 2e⁻ → 2Br⁻
C. Pb²⁺ → Pb + 2e⁻
D. Pb²⁺ + 2e⁻ → Pb
▶️Answer/Explanation
Answer: D. Pb²⁺ + 2e⁻ → Pb
Explanation: During the electrolysis of molten lead(II) bromide, lead ions (Pb²⁺) are reduced at the cathode to form lead metal. The correct equation for this reduction reaction is Pb²⁺ + 2e⁻ → Pb.
Question
The diagram shows an electroplating experiment.
Which row shows the change in mass of each electrode?
| anode | cathode | |
|---|---|---|
| A | decrease | decrease |
| B | decrease | increase |
| C | increase | decrease |
| D | increase | increase |
▶️Answer/Explanation
Answer: B. decrease, increase
Explanation: In electroplating, the anode loses mass as metal ions dissolve into the solution, while the cathode gains mass as metal ions are deposited onto it.
Question
The diagram shows the electrolysis of lead(II) bromide using inert electrodes.
Which statement about this experiment is correct?
A. Electrode X is positively charged.
B. The coloured fumes are produced at the negative electrode.
C. The electrolyte is lead(II) bromide.
D. The grey solid is lead(II) bromide.
▶️Answer/Explanation
Answer: C
Explanation: In the electrolysis of lead(II) bromide, the electrolyte is lead(II) bromide (PbBr2). The grey solid formed is lead metal, which is deposited at the cathode (negative electrode), and the coloured fumes are bromine gas, which is produced at the anode (positive electrode).
Question
Concentrated aqueous sodium chloride is electrolysed using inert electrodes. Which row identifies the product at each electrode?
| product at anode | product at cathode | |
|---|---|---|
| A | chlorine | sodium |
| B | hydrogen | chlorine |
| C | sodium | chlorine |
| D | chlorine | hydrogen |
▶️Answer/Explanation
Answer: D. chlorine and hydrogen
Explanation: During the electrolysis of concentrated aqueous sodium chloride, chlorine gas is produced at the anode, and hydrogen gas is produced at the cathode.
Question
What is the electrolyte that is used when a nickel spoon is electroplated with copper?
A. copper
B. copper sulfate solution
C. nickel sulfate solution
D. nickel
▶️Answer/Explanation
Answer: B
Explanation: Copper sulfate solution is used as the electrolyte in the electroplating process. It provides copper ions (Cu2+) that are reduced to form a copper coating on the nickel spoon.
Question
The electrolysis of concentrated aqueous sodium chloride is shown.
Which statement describes the product at the cathode?
A. It is a colourless gas that pops with a lighted splint.
B. It is a colourless gas that relights a glowing splint.
C. It is a grey solid.
D. It is a pale green gas that bleaches litmus paper.
▶️Answer/Explanation
Answer: A
Explanation: During the electrolysis of concentrated aqueous sodium chloride, hydrogen gas is produced at the cathode. Hydrogen is a colourless gas that pops with a lighted splint.