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 10 of 35
- A. 50 s
- B. 75 s
- C. 125 s
- D. 100 s
Explanation: The change in moles of Cd²⁺ is (0.2 - 0.1.M) × 0.5L = 0.05 mol. The reaction Cd²⁺ + 2e⁻ → Cd requires 2 moles of electronsper mole of Cd…
Correct answer: 100 s- A. Ohm⁻¹·cm⁻¹
- B. Ohm·cm
- C. Ohm·cm⁻¹
- D. Ohm⁻¹·cm
Explanation: Specific conductance, or conductivity (κ., is the reciprocal of resistivity (ρ..
Correct answer: Ohm⁻¹·cm⁻¹- A. 29.5 x 10⁻²
- B. 10
- C. 10¹⁰
- D. 29.5 x 10¹⁰
Explanation: The relationship is ΔG° = nFE°_cell = -RTlnK. This simplifies to logK = nE°/0.0592. Plugging in the values, logK = (2 × 0.295.
Correct answer: 10¹⁰- A. 1
- B. 2
- C. 3
- D. 4
Explanation: The overall reaction is 2H₂ + O₂ → 2H₂O. The half-reaction for hydrogen oxidation is H₂ → 2H⁺ + 2e⁻.
Correct answer: 2- A. 4.305 A
- B. 17.22 A
- C. 8.61 A
- D. 2.1525 A
Explanation: First, find the moles of H₂ produced per second using the molar volume at STP.
Correct answer: 8.61 A- A. Zn + H2SO4(dil) ⟶ ZnSO4 + H2
- B. F2 + 2KCl ⟶ 2KF + Cl2
- C. Cu + H2SO4 ⟶ CuSO4 + H2
- D. Cl2 + 2KBr ⟶ 2KCl + Br2
Explanation: Copper (Cu) is below hydrogen in the electrochemical series, meaning it cannot displace hydrogen from dilute sulfuric acid (H2SO4).
Correct answer: Cu + H2SO4 ⟶ CuSO4 + H2- A. O₂ at the cathode
- B. H₂ at the cathode
- C. H₂ at the anode
- D. No gas
Explanation: At cathode → reduction → H₂At anode → oxidation → O₂.
Correct answer: H₂ at the cathode- A. Mg + 2HCl ⟶ MgCl2 + H2
- B. MgO + 2HCl ⟶ MgCl2 + H2O
- C. Cu + 4HNO3 ⟶ Cu(NO3)2 + 2H2O + 2NO2
- D. 2Mg + O2 ⟶ 2MgO
Explanation: The reaction MgO + 2H2O →MgCl2+ 2H2O is a double displacement reaction.
Correct answer: MgO + 2HCl ⟶ MgCl2 + H2O- A. Cu + HNO3 → Cu(NO3)2 + NO + H2O
- B. I2 + OH- → IO- + I- + H2O
- C. Cl2 + I2 → 2Cl
- D. Zn + 2HCl → ZnCl2
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. C12H22O11 -------> 12C+11H2O
- B. S+H2SO4 ⟶ 3SO2 + 2H2O
- C. Cu+H2SO4 ⟶ CuSO4+SO2+ 2H2O
- D. All of the above
Explanation: In this reaction, H₂SO₄ is acting as an oxidizing agent because it causes copper (Cu) to lose electrons and be oxidized from Cu to…
Correct answer: Cu+H2SO4 ⟶ CuSO4+SO2+ 2H2O- A. -2, -1
- B. +2, -1
- C. -1, +2
- D. +2, +1
Explanation: In OF₂, fluorine is the most electronegative element and is assigned -1, making oxygen +2.
Correct answer: +2, -1- A. Cu⇒Cu2+ +2e
- B. 2SO-24 + 2H2O⇒2H2SO4 + O2 + 4e
- C. 2H2O ⇒O2 + 4H+ + 4e
- D. 2Cl- ⇒Cl2 + 2e
Explanation: The reaction occurring at the anode when the electrolysis of an aqueous solution containing Na2SO4 and CuSO4 is done using a Pt electrode…
Correct answer: 2H2O ⇒O2 + 4H+ + 4e- A. A
- B. B
- C. C
- D. D
Explanation: The graph shown by Option A represents a linear increase in mass over time, which is correct.
Correct answer: A- A. H2 + Cl2 → 2HCl
- B. H2 + C2H4 → C2H6
- C. 2Na + H2 → 2NaH
- D. N2 + 3H2 → 2NH3
Explanation: In this reaction, hydrogen's oxidation number changes from 0 in H2 to -1 in NaH, indicating it is reduced and thus acts as an oxidizing…
Correct answer: 2Na + H2 → 2NaH- A. A
- B. B
- C. C
- D. D
Explanation: The given figure shows (Cu + Zn) electrode connected with SHE. If Zn electrode act as anode, then Hydrogen gas will evolve at cathode.
Correct answer: D- A. Emf of cell
- B. Oxidation potential
- C. Reduction potential
- D. Redox potential
Explanation: The strength of an oxidizing agent is determined by its ability to accept electrons from other substances, causing them to undergo…
Correct answer: Reduction potential- A. Bromine appears at the cathode
- B. Lead is deposited at the cathode
- C. Lead appears at the anode
- D. None of the given options
Explanation: Fused lead bromide undergoes electrolysis which means splitting of ions using electrical energy and movement to ions to respective…
Correct answer: Lead is deposited at the cathode- A. Electroplating
- B. Conductivity
- C. Galvanizing
- D. Metallurgy
Explanation: In electroplating, we have the object replacing the cathode and the metal, the anode.
Correct answer: Electroplating- A. Ammeter
- B. Voltmeter
- C. Galvanometer
- D. Calorimeter
Explanation: A voltmeter is an instrument used for measuring the electric potential difference between two points in an electric circuit.
Correct answer: Voltmeter- A. NH2OH
- B. N2H4
- C. HNO3
- D. NH3
Explanation: HNO3 has the highest oxidation state of nitrogen atom:+1+x+(-6)=0x=+5In NH3, N2H4, and NH2OH, the oxidation states, when calculated the…
Correct answer: HNO3