Free Electrochemistry MCQs with Answers
696 Electrochemistry MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Electrochemistry describes electron transfer through oxidation and reduction, identifies oxidizing and reducing agents, and applies oxidation numbers to balance redox equations. It also covers electrode potential and the standard hydrogen electrode, which provides the reference for comparing the reduction tendencies of other electrodes.
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Read the Electrochemistry notesFree MDCAT chapter notes with key terms696 questions · page 4 of 35
- A. dry cell
- B. galvanic cell
- C. electrolytic cell
- D. A and B
Explanation: When aluminium and copper are connected in the presence of an electrolyte, aluminium is oxidised and copper acts as the site of reduction…
Correct answer: galvanic cell- A. corrode slowly
- B. corrode rapidly
- C. does not corrode easily
- D. none of these
Explanation: A pure metal generally resists corrosion more readily than an impure metal because local galvanic cells are less likely to form between…
Correct answer: does not corrode easily- A. MnO2
- B. Zn
- C. AgO2
- D. cadmium
Explanation: In an alkaline battery, zinc is oxidized at the anode: Zn -> Zn2+ + 2e-.
Correct answer: Zn- A. 1.25g/cm3
- B. 1.3g/cm3
- C. 1.20g/cm3
- D. 1.15g/cm3
Explanation: The sulfuric acid electrolyte of a lead-acid accumulator has a density of about 1.25 g/cm3 under the commonly quoted operating condition.
Correct answer: 1.25g/cm3- A. rechargeable
- B. non rechargeable
- C. electrolytic cell
- D. Daniel cell
Explanation: A secondary cell can be recharged because its electrode reactions are reversible, allowing electrical energy to restore the original…
Correct answer: rechargeable- A. electrons
- B. anion
- C. current
- D. ions
Explanation: A salt bridge contains an inert electrolyte whose cations and anions migrate to maintain electrical neutrality in the two half-cells, so…
Correct answer: ions- A. free electrons
- B. ions
- C. metals
- D. electrodes
Explanation: In an electrolytic solution, dissolved ions move toward oppositely charged electrodes and carry charge through the solution.
Correct answer: ions- A. Pressure increases
- B. Dilution decreases
- C. Dilution increases
- D. None
Explanation: Dilution increases the degree of dissociation of a weak electrolyte because the lower concentration reduces the tendency of oppositely…
Correct answer: Dilution increases- A. The flow of electrons takes place from copper to zinc
- B. E0red of copper electrode is less than that of zinc electrode
- C. Zinc acts as an anode and copper as cathode
- D. All are correct
Explanation: In a Zn-Cu galvanic cell, zinc is oxidised at the anode and copper ions are reduced at the cathode, so zinc is the anode and copper is the…
Correct answer: Zinc acts as an anode and copper as cathode- A. wire
- B. salt bridge
- C. electric circuit
- D. no connection exists
Explanation: The two half-cells are connected internally by a salt bridge, which permits ion migration and maintains electrical neutrality.
Correct answer: salt bridge- A. 40%
- B. 25%
- C. 30%
- D. 50%
Explanation: The electrolyte of a charged lead accumulator is aqueous sulfuric acid with a concentration commonly taken as about 30% by mass in basic…
Correct answer: 30%- A. 1.5 volts
- B. 2 volts
- C. 3 volts
- D. 1 volts
Explanation: A single lead-acumulator cell produces about 2 volts because the lead dioxide and lead electrode reactions have a potential difference of…
Correct answer: 2 volts- A. secondary cell
- B. primary cell
- C. voltaic cell
- D. both A & C
Explanation: A lead accumulator is a secondary cell because its discharge reaction can be reversed by passing an external current.
Correct answer: both A & C- A. periodic table
- B. groups
- C. periods
- D. electrochemical series
Explanation: The electrochemical series arranges elements or ions according to their standard electrode potentials, measured relative to the standard…
Correct answer: electrochemical series- A. by addition of fresh solution
- B. by replacing external circuit with external source of electricity
- C. by removal of solution
- D. by heating it
Explanation: A rechargeable voltaic cell is restored by forcing the reverse redox reaction with an external source of electrical energy.
Correct answer: by replacing external circuit with external source of electricity- A. external electric circuit
- B. salt bridge
- C. movement of ions
- D. all of the above
Explanation: In a galvanic cell, oxidation at the anode releases electrons and reduction at the cathode consumes them, so electrons travel through the…
Correct answer: external electric circuit- A. spontaneous reaction
- B. non-wpontaneous reaction
- C. neutralization
- D. all of above
Explanation: An electrolytic cell uses an external electrical supply to drive a non-spontaneous redox reaction.
Correct answer: non-wpontaneous reaction- A. neutralization
- B. oxidation
- C. reduction
- D. both B & C
Explanation: A voltaic cell produces electricity through a coupled redox process: oxidation occurs at the anode and reduction occurs at the cathode.
Correct answer: both B & C- A. Free electrons
- B. Free molecules
- C. Free ions
- D. Atoms of Na and Cl
Explanation: Molten NaCl contains mobile Na+ and Cl- ions, which migrate to opposite electrodes and carry charge through the liquid.
Correct answer: Free ions- A. Chemical energy is converted into electricity
- B. Chemical energy is converted into heat
- C. Electrical energy is converted into chemical energy
- D. Electrical energy is converted into heat
Explanation: A galvanic cell converts the chemical energy released by a spontaneous redox reaction into electrical energy.
Correct answer: Chemical energy is converted into electricity