Electrochemistry Practice Questions
18 free Electrochemistry practice questions for the General Science. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
What is the primary purpose of a galvanic (voltaic) cell?
- A Convert electrical energy into chemical energy
- B Convert chemical energy into electrical energy
- C Store thermal energy for later use
- D Measure the electrical resistance of a solution
Correct answer: Convert chemical energy into electrical energy
A galvanic cell converts chemical energy from spontaneous redox reactions into electrical energy. Electrons flow through an external circuit from the anode to the cathode.
In an electrochemical cell, where does oxidation occur?
- A At the cathode
- B In the salt bridge
- C At the anode
- D In the wire
Correct answer: At the anode
Oxidation always occurs at the anode in an electrochemical cell. At this electrode, electrons are released and flow through the external circuit.
Which electrode is the site of reduction in an electrochemical cell?
- A Anode
- B Cathode
- C Salt bridge
- D Electrolyte
Correct answer: Cathode
Reduction occurs at the cathode where electrons are gained by chemical species. This process happens simultaneously with oxidation at the anode.
What is the role of the salt bridge in a galvanic cell?
- A Generate electrons for the external circuit
- B Increase the voltage of the cell
- C Store charge for later use
- D Maintain electrical neutrality
Correct answer: Maintain electrical neutrality
The salt bridge allows ions to move between half-cells to maintain electrical neutrality. Without it, charge buildup would stop the electron flow.
Which type of reaction occurs in electrochemical cells?
- A Neutralization reaction
- B Precipitation reaction
- C Hydrolysis reaction
- D Redox reaction
Correct answer: Redox reaction
Electrochemical cells operate through oxidation-reduction (redox) reactions. One substance loses electrons while another gains electrons.
Which device converts electrical energy into chemical energy?
- A Galvanic cell
- B Hydrogen fuel cell
- C Photovoltaic solar cell
- D Electrolytic cell
Correct answer: Electrolytic cell
An electrolytic cell uses electrical energy to drive a non-spontaneous chemical reaction. This process is commonly used in electrolysis.
Which metal is commonly used as the electrode in a standard hydrogen electrode?
- A Copper
- B Magnesium
- C Platinum
- D Iron
Correct answer: Platinum
Platinum is used in the standard hydrogen electrode because it is chemically inert and conducts electricity well. It provides a surface for hydrogen gas reactions.
What is the standard electrode potential measured relative to?
- A Standard copper electrode
- B Standard silver chloride electrode
- C Standard hydrogen electrode
- D Standard calomel electrode
Correct answer: Standard hydrogen electrode
Standard electrode potentials are measured relative to the standard hydrogen electrode (SHE), which is assigned a potential of exactly 0 volts. Secondary references such as the calomel and silver chloride electrodes are convenient in the laboratory, but their own potentials are calibrated against the SHE.
Which process is used to coat a metal surface with another metal using electricity?
- A Electroplating
- B Electrolysis
- C Electrorefining
- D Anodizing
Correct answer: Electroplating
Electroplating uses an electric current to deposit a thin layer of metal onto another metal surface. It improves corrosion resistance and appearance.
Which ion moves toward the cathode during electrolysis?
- A Anion
- B Neutral molecule
- C Electron
- D Cation
Correct answer: Cation
Cations are positively charged ions and are attracted to the negatively charged cathode. At the cathode, they gain electrons and undergo reduction.
Which ion moves toward the anode during electrolysis?
- A Anion
- B Cation
- C Neutral atom
- D Proton
Correct answer: Anion
Anions carry negative charges and move toward the positively charged anode. At the anode, they lose electrons and undergo oxidation.
Which law relates the amount of substance deposited during electrolysis to the electric charge passed?
- A Faraday's Law
- B Boyle's Law
- C Ohm's Law
- D Avogadro's Law
Correct answer: Faraday's Law
Faraday's laws of electrolysis state that the amount of substance deposited is proportional to the electric charge passed through the electrolyte.
What unit is used to measure electric charge in electrochemistry?
- A Volt
- B Ampere
- C Coulomb
- D Electronvolt
Correct answer: Coulomb
The coulomb is the SI unit of electric charge. In electrochemistry, the amount of charge determines how much substance is produced or consumed.
Which of the following best describes oxidation?
- A Loss of electrons
- B Gain of electrons
- C Gain of protons
- D Loss of neutrons
Correct answer: Loss of electrons
Oxidation is defined as the loss of electrons during a chemical reaction. This process occurs at the anode in electrochemical cells.
Which of the following best describes reduction?
- A Gain of electrons
- B Loss of electrons
- C Loss of protons
- D Gain of neutrons
Correct answer: Gain of electrons
Reduction involves the gain of electrons by a substance. It occurs at the cathode during electrochemical reactions.
Which device produces electricity from continuous chemical reactions involving fuel?
- A Fuel cell
- B Battery
- C Electrolytic cell
- D Capacitor
Correct answer: Fuel cell
A fuel cell generates electricity through chemical reactions between a fuel and an oxidizing agent. Unlike batteries, it operates continuously as long as fuel is supplied.
Which electrochemical process is used to extract metals like aluminum from their ores?
- A Electrolysis
- B Electroplating
- C Electrorefining
- D Corrosion
Correct answer: Electrolysis
Electrolysis is used in processes like the Hall-Héroult method to extract aluminum from alumina. Electrical energy drives the reduction of metal ions.
What happens to electrons in the external circuit of a galvanic cell?
- A They flow from cathode to anode
- B They flow from anode to cathode
- C They remain stationary
- D They move through the salt bridge
Correct answer: They flow from anode to cathode
Electrons produced at the anode during oxidation travel through the external circuit to the cathode. At the cathode, they are consumed in the reduction reaction.