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 29 of 35
561. Electrolysis is a:
- A. Spontaneous reactions
- B. Oxidation-reduction reaction
- C. Reduction reaction
- D. Oxidation reaction
Explanation: Electrolysis is a process where an electric current is passed through a substance to effect a chemical change.
Correct answer: Oxidation-reduction reaction- A. E
- B. E-1
- C. E°
- D. A
Explanation: The standard electrode potential, denoted by 'E°', represents the potential of an electrode reaction under standard conditions, which…
Correct answer: E°- A. Balance out all the Reactants
- B. Write the skeleton Equation
- C. Calculate the oxidation number
- D. Identify the elements
Explanation: b) Write the skeleton Equation: This option is a correct step in balancing a redox equation.
Correct answer: Write the skeleton Equation- A. NaCl + AgNO3 → NaNO3 + AgCl
- B. 2Cl- → Cl2 + 2e-
- C. 2Na + Cl2 → 2NaCl
- D. Na + 1e- → Na
Explanation: The oxidation number of sodium increases from 0 (on the reactants side) to +1 (on the products side), hence sodium is being oxidised.
Correct answer: 2Na + Cl2 → 2NaCl- A. H2O is the reducing agent
- B. H2O is the oxidising agent
- C. Carbon is the oxidising agent
- D. Oxidation-reaction does not occur
Explanation: In the given reaction, H2O is reduced to H2, meaning it gains hydrogen atoms.
Correct answer: H2O is the oxidising agent- A. Cu + HNO3 → Cu(NO3)2 + NO + H2O
- B. I2 + OH- → IO- + I- + H2O
- C. Cl2 + I2 → 2ClI
- D. Zn + 2HCl → ZnCl2 + H2
Explanation: In a disproportionation reaction, a single element in one oxidation state is simultaneously oxidized and reduced to form two different…
Correct answer: I2 + OH- → IO- + I- + H2O- A. A
- B. B
- C. C
- D. D
Explanation: Cu + H2SO4 → CuO + H2O + SO2 (H2SO4 act as oxidant) CuO + H2SO4 → CuSO4 + H2O (H2SO4 act as acid)
Correct answer: C- A. Both half-cell reactions take place simultaneously
- B. Of resistance of the wire
- C. A reaction does not take place on its own
- D. None of the above
Explanation: It is impossible to measure the actual voltage of any half-cell by itself because a reaction does not take place on its own.
Correct answer: A reaction does not take place on its own- A. 4.305 amp
- B. 17.22 amp
- C. 8.61 amp
- D. 2.1525 amp
Explanation: The correct answer is 8.61 amp. To determine this, we utilize Faraday's laws of electrolysis, which state that the amount of substance…
Correct answer: 8.61 amp- A. Less than anode
- B. The same as anode
- C. More than anode
- D. Always zero
Explanation: At cathode reduction takes place hence it has greater Eered than anode.
Correct answer: More than anode- A. A
- B. B
- C. C
- D. D
Explanation: The correct answer is Option C. Copper (Cu) is below hydrogen in the electrochemical series, which means it cannot displace hydrogen from…
Correct answer: C- A. A
- B. B
- C. C
- D. D
Explanation: The reaction MgO + 2H2O → MgCl2 + 2H2O is a double displacement reaction.
Correct answer: B- A. Anode
- B. Cathode
- C. At the surface of the electrolyte
- D. None of these
Explanation: In electrochemical cells, reduction occurs at the cathode, which is the electrode where electrons are gained by the chemical species.
Correct answer: Cathode- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Following is the solution to this question:
Correct answer: Option B- A. VO2+ → V2O3
- B. Na → Na+
- C. CrO4-2 → Cr2O72-
- D. Zn2+ → Zn
Explanation: 2Cr6+ → Cr26+ ; Neither oxidation nor reduction.
Correct answer: CrO4-2 → Cr2O72-- A. The law is valid at infinite dilution
- B. The law is valid for weak electrolytes only
- C. The basis of law is independent migration of ions
- D. None of the above
Explanation: The law is valid for weak and strong electrolytes both.
Correct answer: The law is valid for weak electrolytes only- A. Zn(s)
- B. Cr(s)
- C. H2(g)
- D. Fe 2+(aq)
Explanation: Zn2+(aq) is having minimum reduction potential. So oxidation potential of Zn(s) will be maximum and it will be strongest reducing agent.
Correct answer: Zn(s)- A. 0.2 mole of 2 Cu+ will go into solution
- B. 560 ml O2 liberate
- C. No loss in weight
- D. 2 gram of copper goes into solution as Cu2+
Explanation: During electrolysis of CuSO4 solution using Cu electrodes, the cell reaction is: Anode: Cu (s) → Cu++ + 2e- Cathode: Cu++(aq) + 2e- →…
Correct answer: 2 gram of copper goes into solution as Cu2+- A. H2
- B. CI2
- C. O2
- D. Na
Explanation: For aqueous solution of NaCl at cathode.H2O is reduced to H2 as its Ered is higher than Na+. 2H2O + 2e- → H2 + 2OH-
Correct answer: H2- A. Electromotive force
- B. Electrode potential
- C. Cell potential
- D. Both A and C
Explanation: Emf or cell potential is the force used to drive electron in a circuit.
Correct answer: Both A and C