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 7 of 35
- A. lead will act as anode and silver as cathode
- B. lead will act as cathode and silver as anode
- C. silver will act as cathode because it has greater reduction potential
- D. lead will act as anode because it has lesser reduction potential
Explanation: To determine which element will act as the anode and which as the cathode, you can look at the standard reduction potentials for each…
Correct answer: silver will act as cathode because it has greater reduction potential- A. Ni , Ni2+ ║ Mn2+ , Mn
- B. Mn , Mn2+ ║ Ni2+ , Ni
- C. Mn2+ , Ni ║ Ni , Ni2+
- D. Ni , Ni ║ Mn , Mn2+
Explanation: In a voltaic cell, the half-reaction with the higher standard reduction potential (E) acts as the cathode (where reduction occurs), and…
Correct answer: Mn , Mn2+ ║ Ni2+ , Ni- A. oxidation state of N in NO and N2O5 is +5 and +2 respectively
- B. oxidation state of N in NO and N2O5 is +1 and +5 respectively
- C. oxidation state of N in NO and N2O5 is +2 and +5 respectively
- D. oxidation state of N in NO and N2O5 is +2 and +4 respectively
Explanation: To determine the oxidation states of nitrogen (N) in compounds, you can use certain rules.In NO (nitric oxide), the oxidation state of…
Correct answer: oxidation state of N in NO and N2O5 is +2 and +5 respectively- A. It increases with an increase in the concentration of the cathodic solution
- B. It increases with an increase in the concentration of the anodic solution.
- C. It increases with an increase in the size of the cathode
- D. It increases with a decrease in the size of the anode
Explanation: The life period of a galvanic cell is determined by various factors, and among the given options, the correct statement is:b.
Correct answer: It increases with an increase in the concentration of the anodic solution.- A. Nelson's cell
- B. Down's cell
- C. Electrolytic cell
- D. Daniel cell
Explanation: This is the correct answer. In an electrolytic cell, a non-spontaneous reaction is forced to occur by the application of an external…
Correct answer: Electrolytic cell- A. Positive
- B. Negative
- C. 0
- D. Infinite
Explanation: The spontaneity of a redox reaction in an electrochemical cell is determined by the cell potential (Ecell).
Correct answer: Positive127. The set of numerical coefficients that balances the chemical equation K2CrO4+HCl K2Cr2O7+KCl+H2O
- A. 1, 1, 2, 2, 1
- B. 2, 2, 1, 1, 1
- C. 2, 1, 1, 2, 1
- D. 2, 2, 1, 2, 1
Explanation: This incorrectly doubles both K₂Cr₂O₇ and KCl, leading to an imbalance in potassium and oxygen on top of the existing hydrogen issue.
Correct answer: 2, 1, 1, 2, 1- A. Free electrons
- B. Fused electrolyte
- C. Charged ions
- D. None
Explanation: Electrolytes are substances that conduct electricity when dissolved in water or molten form.
Correct answer: Charged ions- A. +2.87, +1.08
- B. +0.332, +2.87
- C. -0.78, -1.66
- D. None of these
Explanation: The standard reduction potential of fluorine (Fz) is +2.87 V, and the standard reduction potential of bromine (Brz) is + 1.08 V.
Correct answer: +2.87, +1.08- A. Galvanizing
- B. Cathode Coating
- C. Neutral Suspension
- D. All of these
Explanation: Galvanizing: This is a process where a thin layer of zinc is coated onto iron or steel to protect it from corrosion.
Correct answer: Galvanizing- A. +6, +3
- B. +5, +2
- C. +7, +3
- D. +6, +4
Explanation: K₂Cr₂O₇ (Potassium Dichromate):The oxidation number of potassium (K) is always +1.The oxidation number of oxygen (O) is usually -2.Let the…
Correct answer: +6, +4- A. +2
- B. +6
- C. +4
- D. -2
Explanation: H₂SO₄ (Sulfuric Acid):The oxidation number of hydrogen (H) is +1.The oxidation number of oxygen (O) is -2.Let the oxidation number of…
Correct answer: +6- A. 12
- B. 8
- C. 7
- D. 6
Explanation: K₂MnO₄ (Potassium Manganate):The oxidation number of potassium (K) is always +1.The oxidation number of oxygen (O) is usually -2.Let the…
Correct answer: 6- A. Anode to cathode through external circuit
- B. Cathode to anode through external circuit
- C. Anode to cathode through salt bridge
- D. Cathode to anode through salt bridge
Explanation: In a galvanic cell, the anode is where oxidation occurs (loss of electrons), and the cathode is where reduction occurs (gain of…
Correct answer: Anode to cathode through external circuit- A. Mn in KMnO₄
- B. K in KCl
- C. Br in Br₂O
- D. Na in NaCl
Explanation: Mn in KMnO₄: Manganese (Mn) in potassium permanganate (KMnO₄) exhibits a valency of +7.
Correct answer: Mn in KMnO₄- A. Tendency of metals to form ions when dissolved in 1M solution of its own solution
- B. Tendency of ions to form atoms when dissolved in 1M solution of its metal
- C. Both a and b
- D. None of these
Explanation: Electrode Potential: The tendency of a metal to lose electrons and become oxidized when it is in contact with a solution of its ions.
Correct answer: Tendency of metals to form ions when dissolved in 1M solution of its own solution- A. +2
- B. -2
- C. -1
- D. +1
Explanation: Mg₃P₂O₈ (Magnesium Pyrophosphate):The oxidation number of magnesium (Mg) is +2.The oxidation number of oxygen (O) is -2
Correct answer: +1- A. +7
- B. -7
- C. -1
- D. +1
Explanation: Chlorine (Cl) is a halogen and can exhibit a range of oxidation states, from -1 to +7.
Correct answer: +7- A. 0
- B. 1
- C. 2
- D. None of these
Explanation: In the diatomic molecule I₂, iodine (I) is in its elemental form. Elements in their elemental state have an oxidation number of 0.
Correct answer: 0- A. 348K
- B. 298K
- C. 20K
- D. 235K
Explanation: Standard Electrode Potential is defined as the potential difference between a metal electrode and its solution of ions at standard…
Correct answer: 298K