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 17 of 35
- A. Anode
- B. Cathode
- C. Towards the bottom of the cell
- D. Towards the walls of the cell
Explanation: Anode attracts all the negative ions towards itself, it is positive in nature.
Correct answer: Anode- A. A negative charge
- B. A net positive charge
- C. Neutral
- D. None of these options are correct
Explanation: The zinc electrode in the left beaker, (having more tendency to give off electrons) loses electrons and goes through oxidation, hence…
Correct answer: A net positive charge- A. 1
- B. -1
- C. Zero
- D. 2
Explanation: The oxidation number or state of hydrogen in all its compounds except metal hydrides is +1. In metal hydride it is -1.
Correct answer: -1- A. Hydrogen gas
- B. Hydrogen Atom
- C. Water
- D. Both B and C
Explanation: By accepting an electron, hydronium ions are converted into hydrogen atoms, and water is released.H3O + e- → H +H2O
Correct answer: Both B and C- A. Cu + Zn+2 → Cu+2 + Zn
- B. Cu+2 + Zn+2 → Cu + Zn
- C. Cu+2 + Zn → Cu + Zn+2
- D. Cu+2 + Zn+2 → Cu + Zn+2
Explanation: The half cell equation with the lower Eo is the anode. Electrons travel from cathode to anode.
Correct answer: Cu+2 + Zn → Cu + Zn+2- A. Na
- B. Al
- C. Pb
- D. Cu
Explanation: Copper deposits at cathode and chlorine is liberated at anode.During the electrolysis of aqueous CuCl2, Cu²⁺ ions and H⁺ ions are present…
Correct answer: Cu- A. 0
- B. +2
- C. -2
- D. -1
Explanation: In MgCl2, the oxidation state of Mg is +2 since it is a Group 2 element and tends to lose two electrons to attain a noble gas…
Correct answer: -1- A. Pass the electric current
- B. Prevent the flow of ions
- C. Mix solution of two half cells
- D. Allow movement of ions between two half cells
Explanation: A salt bridge keeps the solutions electrically neutral and allows the free flow of ions from one cell to another.
Correct answer: Allow movement of ions between two half cells- A. Oxidation states
- B. Reductions
- C. Electrode
- D. Negative charges
Explanation: Since an atom loses an electron, their oxidation state becomes more positive (increases).
Correct answer: Oxidation states- A. Copper to zinc electrode
- B. Right to left
- C. Porous partition to zinc electrode
- D. Zinc to copper electrode
Explanation: The electrons flow from the oxidation reaction (Zn (s) --> Zn2+ (aq) + 2 e-) to the reduction half-cell (Cu2+ (aq) + 2 e- --> Cu (s)).
Correct answer: Zinc to copper electrode- A. NaCl + AgNO3 → NaNO3 + AgCl2
- 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. FeSO4 and FeCl3
- B. FeCl2 and FeCl3
- C. FeSO4 and FeCl2
- D. Fe2(SO4)3 and FeSO4
Explanation: In both FeSO4 and FeCl2, the oxidation state of Fe is +2.
Correct answer: FeSO4 and FeCl2- A. Hydrogen electrode to copper electrode
- B. Copper electrode to hydrogen electrode
- C. Hydrogen electrode to HCl solution
- D. CuSO4 solution to hydrogen electrode
Explanation: The reduction potential of copper is greater than that of hydrogen so in that case, the copper electrode will act as a cathode and S.H.E…
Correct answer: Hydrogen electrode to copper electrode- A. Cathode
- B. Anode
- C. Solution
- D. Both Cathode and Anode
Explanation: Copper is purified by electrolysis . Electricity is passed through solutions containing copper compounds, such as copper sulfate.
Correct answer: Anode- A. 𝐾𝑀𝑛𝑂4
- B. 𝐾𝐼
- C. 𝐻2𝑆𝑂4
- D. 𝐾𝐼 and 𝐻2𝑆𝑂4 both
Explanation: Reducing agent is the one which has the ability to give its unshared pair of electrons to other species to reduce them.
Correct answer: 𝐾𝐼- A. The reaction is non spontaneous and feasible
- B. The reaction is non spontaneous and not feasible
- C. The reaction is spontaneous and feasible
- D. The reaction is spontaneous and not feasible
Explanation: The energy associated with the separation/transfer of charge is the property of potential, E.
Correct answer: The reaction is non spontaneous and not feasible- A. -6
- B. 7
- C. 9
- D. 10
Explanation: Since the oxidation state of potassium and oxygen are +1 & -2 respectively.
Correct answer: 7- A. -3 and +5
- B. +5 and-3
- C. -3 & -3
- D. Zero
Explanation: NH₄⁺ N + 4 = 1 N = 1-4 N = 3 NO3- N + 3(-2)= -1 N - 6 = -1 N = -1 + 6 N= 5
Correct answer: -3 and +5- A. Reduction takes place at zinc electrode
- B. Oxidation takes place at copper electrode
- C. Reduction takes place at copper electrode
- D. Both Reduction takes place at zinc electrode and Oxidation takes place at copper electrode
Explanation: A galvanic cell is made by joining two half cells. Cu2+ has a higher reduction potential so it is reduced and reduction talks place at Cu…
Correct answer: Reduction takes place at copper electrode- A. Mn7+
- B. KMnO2+
- C. MnO2
- D. Mn1+
- E. Mn4+
Explanation: Equation for reduction of KMnO4 in acidic medium:8H+ + MnO4- + 5e- ----> Mn2+ + 4H2OHere in MnO4- the oxidation state of Mn is +7, and it…
Correct answer: Mn7+