Chapter-5 Electrochemistry — Online MCQ Test
CHEMISTRY · Grade 10 · IGCSE cambridge
Practice Chapter-5 Electrochemistry with a free chapter-wise online MCQ test.
This chapter covers: Electrolysis of molten compounds and solutions electroplating and uses of electrolysis in industry..
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter-5 Electrochemistry — Important Questions & Answers
What is electrolysis?
- A. The process of breaking down a compound using electrical energy
- B. The process of combining two elements using heat
- C. The process of separating metals from ore by heating
- D. The process of neutralizing acids and bases
Answer: A. The process of breaking down a compound using electrical energy
Electrolysis is the decomposition of a chemical compound by passing an electric current through it. This process uses electrical energy to break chemical bonds.
Electrolysis is the decomposition of a chemical compound by passing an electric current through it. This process uses electrical energy to break chemical bonds.
Which of the following is the correct definition of the anode in electrolysis?
- A. The negative electrode where reduction occurs
- B. The positive electrode where oxidation occurs
- C. The electrode connected to the negative terminal of the battery
- D. The electrode where cations are deposited
Answer: B. The positive electrode where oxidation occurs
The anode is the positive electrode in an electrolytic cell where oxidation takes place and electrons are removed from ions or atoms.
The anode is the positive electrode in an electrolytic cell where oxidation takes place and electrons are removed from ions or atoms.
Which statement about electroplating is correct?
- A. The object to be plated is connected to the positive terminal (anode)
- B. The object to be plated is connected to the negative terminal (cathode)
- C. The plating metal is made the cathode
- D. Both electrodes must be made of the same material
Answer: B. The object to be plated is connected to the negative terminal (cathode)
In electroplating, the object to be plated is made the cathode (negative electrode) where metal ions are reduced and deposited as a coating.
In electroplating, the object to be plated is made the cathode (negative electrode) where metal ions are reduced and deposited as a coating.
In the electrolysis of molten lead bromide, what are the products at the electrodes?
- A. Lead at cathode, bromine at anode
- B. Bromine at cathode, lead at anode
- C. Hydrogen at cathode, oxygen at anode
- D. Lead bromide at both electrodes
Answer: A. Lead at cathode, bromine at anode
At cathode: Pb²⁺ + 2e⁻ → Pb (lead metal deposited). At anode: 2Br⁻ - 2e⁻ → Br₂ (bromine gas produced). In molten salts, the ions themselves are electrolyzed, not water.
At cathode: Pb²⁺ + 2e⁻ → Pb (lead metal deposited). At anode: 2Br⁻ - 2e⁻ → Br₂ (bromine gas produced). In molten salts, the ions themselves are electrolyzed, not water.
A technician electroplates a steel component with chromium using a chromium anode and dilute chromic acid as electrolyte. After 2 hours at 5A, minimal coating is observed. Which factor could be responsible for poor electroplating?
- A. The steel component was made the anode instead of the cathode
- B. The chromium anode was not pure
- C. The current density was too high
- D. The electrolyte concentration was too high
Answer: A. The steel component was made the anode instead of the cathode
If the steel component is incorrectly made the anode, it will be oxidized and dissolved rather than being coated. The cathode should be the object to be plated, where reduction occurs and metal is deposited.
If the steel component is incorrectly made the anode, it will be oxidized and dissolved rather than being coated. The cathode should be the object to be plated, where reduction occurs and metal is deposited.