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 33 of 35
641. KMnO4 acts as a/an:
- A. Reducing agent
- B. Excellent precipitating reagent
- C. Germicide
- D. Oxidizing agent
Explanation: A is incorrect as KMnO4 isnt a reducing agent.B is incorrect as KMnO4 isnt a precipitating agent.C is incorrect as KMnO4 isnt used in…
Correct answer: Oxidizing agent- A. -8
- B. +8
- C. -6
- D. +6
Explanation: The oxidation of sulphur is 6+:it is because the oxide ion has a charge of -2 making it -8 overall, for four oxide ions.
Correct answer: +6- A. 5+
- B. 2+
- C. 3+
- D. 3-
Explanation: NO3N = xO = - 2x + (-2) × 3 = - 1x + (- 6) = - 1x - 6 = - 1x = - 1 + 6x = 5
Correct answer: 5+- A. -1, +1
- B. -1, +3
- C. -1, +5
- D. +1, +5
Explanation: In NaCl, Na has an oxidation state of +1 so Cl is -1 and in NaClO3, Na is +1 and O is -6 while Cl is an unknown x.
Correct answer: -1, +5- A. Copper metal
- B. Copper ions
- C. Hydrogen
- D. Oxygen
Explanation: Since reduction takes place cupric ions present in the electrolyte gain two electrons and get converted into copper metal.
Correct answer: Copper metal- A. Cd
- B. Ni(OH)2
- C. Ni
- D. NiO2
Explanation: Explanation:The correct option is NiO2 because the cathode in a nickel-cadmium battery is typically composed of nickel oxyhydroxide…
Correct answer: NiO2- A. Tin plating
- B. Zinc plating
- C. Nickel plating
- D. Copper plating
Explanation: Explanation:The most durable metal plating on iron to protect against corrosion is zinc plating.
Correct answer: Zinc plating- A. Hydrolysis reaction
- B. Oxidation reaction
- C. Redox reaction
- D. Reduction reaction
Explanation: The correct answer is C: Redox reaction. In a voltaic cell, the production of electricity is due to redox reactions, where oxidation and…
Correct answer: Redox reaction- A. Zn+2 + Cu → Cu+2 + Zn
- B. Zn + MgSO4 → ZnSO4 + Mg
- C. Fe + CuSO4 → FeSO4 + Cu
- D. Cd + MgSO4 → CdSO4 + Mg
Explanation: Fe + CuSO₄ → FeSO₄ + Cu is feasible because iron has a lower reduction potential (-0.44 V) than copper (+0.34 V), meaning iron is more…
Correct answer: Fe + CuSO4 → FeSO4 + Cu- A. Redox Potential
- B. Cell Potential
- C. Oxidation Potential
- D. None of the above
Explanation: Explanation:The emf produced by the Galvanic cell is known as cell potential, which is the difference in reduction potentials of the two…
Correct answer: Cell Potential- A. pH scale
- B. pOH scale
- C. Hydrogen Scale
- D. pKa scale
Explanation: A is incorrect as pH scale is a tool to measure pH(acidity) of a B is incorrect as pOH scale is a tool to measure pOH(alkalinity) of a…
Correct answer: Hydrogen Scale- A. 2H+(aq) + 2e- → H2(g)
- B. H2(g) → 2H+(aq) + 2e-
- C. 2H+(aq) + 2e- → 2H(g)
- D. 2H2- → 2H(g) + 2e-
Explanation: The Standard Hydrogen Electrode (SHE) serves as a benchmark for measuring standard electrode potentials, with a potential of 0 V.
Correct answer: H2(g) → 2H+(aq) + 2e-- A. Oxidation of Ag
- B. Reduction of Cu
- C. Oxidation of Cu
- D. Ionization of Ag
Explanation: When copper wire is placed in silver nitrate solution then the solution becomes blue colored.
Correct answer: Oxidation of Cu- A. Oxidation of Ag
- B. Reduction of Cu
- C. Oxidation of Cu
- D. Reduction of Ag
Explanation: When copper is added to silver nitrate solution, the following reaction takes place:
Correct answer: Oxidation of Cu- A. -6
- B. +6
- C. -4
- D. +4
Explanation: In sulfuric acid (H2SO4), Hydrogen exists in its normal oxidation state of +1 and Oxygen exists in its normal oxidation state of -2.
Correct answer: +6- A. Ag
- B. Au
- C. Al
- D. Zn
Explanation: In a displacement reaction, a more reactive metal can displace a less reactive metal from its salt solution.
Correct answer: Zn- A. -1
- B. +3
- C. +5
- D. -6
Explanation: This has to be calculatedThe oxidation state of Ca is +2, and oxygen is -2, so:(+2) + (2x) + (6 x -2) = 0; calculating this gives x = +5
Correct answer: +5- A. Ag
- B. AU
- C. Pt
- D. Zn
Explanation: A more reactive metal can displace a less reactive metal from its salt in an aqueous solution.
Correct answer: Zn- A. -1
- B. +3
- C. +5
- D. -6
Explanation: In the compound Ca(ClO3)2, calcium has an oxidation state of +2, being a Group 2 metal. Each ClO3- ion must balance to -1 overall charge.
Correct answer: +5- A. +3
- B. +2
- C. +4
- D. +6
Explanation: OPTION B is correct as there six ligands in the compound which is a cyano group having a charge of -1.
Correct answer: +2