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 12 of 35
- A. This potential oxidizes salt
- B. This potential reduces salt
- C. This potential reduces water
- D. This potential oxidizes water
Explanation: The correct reason for the decomposition of salt X in water is that the potential (Ecell = 1.91 V) reduces the salt, leading to the…
Correct answer: This potential reduces salt- A. Fe3+
- B. Ni
- C. Fe2+
- D. Sn
Explanation: Reduction potentials are given. The species with the most negative reduction potential is the strongest reducing agent.
Correct answer: Fe2+- A. The oxidation number of iodine in the iodate ion, IO3-(aq), changes from +5 to +1.
- B. The oxidation number of iodine in the iodide ion I-, changes from -1 to +2
- C. The oxidation number of chlorine in the iodide ion I- , changes from -1 to -2
- D. Iodate ions are oxidized
Explanation: In IO3-, iodine has an oxidation number of +5 which we can calculate from the oxidation number of oxygen which is -2, and the collective…
Correct answer: The oxidation number of iodine in the iodate ion, IO3-(aq), changes from +5 to +1.- A. O2, H2
- B. O2, Na
- C. O2, SO
- D. O2, S2O4-2
Explanation: Explanation: This question can be solved by recalling the order of the electrochemical series: From this, it can be seen that H+ will be…
Correct answer: O2, H2- A. 0.002 g
- B. 0.123 g
- C. 0.012 g
- D. 0.004 g
Explanation: In this scenario, we first find the total number of charges flown through the apparatus.
Correct answer: 0.012 g- A. -1
- B. -2
- C. 0
- D. +1
Explanation: Br2 is a diatomic molecule in its natural state and the oxidation state for all element's natural state is 0.
Correct answer: 0- A. -0.76 volts
- B. 0.00 volts
- C. +1.5 volts
- D. 1.0 volts
Explanation: The standard electrode potential of Hydrogen is 0 at 298K. This is because it acts as a reference point for comparison with any other…
Correct answer: 0.00 volts- A. Emf(oxidation) - Emf(Reduction)
- B. Emf(oxidation) + Emf(Reduction)
- C. Emf(oxidation) x Emf(Reduction)
- D. None of these
Explanation: In an electrochemical cell, the emf is given by Emf(reduction) - Emf(oxidation).or Emf(oxidation) + Emf (Reduction)
Correct answer: Emf(oxidation) + Emf(Reduction)- A. Mechanical Energy
- B. Electromechanical Energy
- C. Electrochemistry
- D. Chemical Energy
Explanation: The conversion of electrical to chemical energy is called electrochemistry.
Correct answer: Electrochemistry- A. Electrons on left hand side
- B. Electron on ride hand side
- C. Both left or right hand side
- D. None of these
Explanation: Each reaction is balanced by adjusting coefficients and adding H2O, H+, and e− in this order: Balance elements in the equation other than…
Correct answer: Both left or right hand side- A. Which are oxidizing
- B. Which are reducing
- C. Which are not taking part in reaction
- D. Which will take part in reaction
Explanation: Only those substances are written in the ion-electron method which will take part in the reaction.
Correct answer: Which will take part in reaction- A. Oxidation
- B. Reduction
- C. Both A and B
- D. None of these
Explanation: The increase in the oxidation state of an atom, through a chemical reaction, is known as oxidation; a decrease in the oxidation state is…
Correct answer: Reduction- A. Oxygen
- B. Hydrogen
- C. Water
- D. Air
Explanation: Hydrolysis is a reaction in which larger molecules react with water to form 2 smaller molecules and leads to the decomposition of both the…
Correct answer: Water- A. Balance out the atoms on each side
- B. Write the skeleton Equation
- C. Calculate the oxidation Number
- D. Identify the elements and their states
Explanation: The following are the steps to balancing redox equations.
Correct answer: Write the skeleton Equation- A. Free electrons
- B. Positive Ions
- C. Negative Ions
- D. Both B and C
Explanation: Electrolyte solution or molten salt can conduct electricity by the process of electrolysis.
Correct answer: Both B and C- A. 2atm
- B. 780 mmHg
- C. 19 Psi
- D. 1.5 atm
Explanation: Molarity= Weight of solute/Vol of sol in L№ of moles of HCl= 27/22.4=1.2054 molesMolarity= 1.2054/0.785=1.5355 M
Correct answer: 1.5 atm- A. 1
- B. 2
- C. 3
- D. zero
Explanation: Alkali Metals are Group 1 metals and lose an electron to form compounds.
Correct answer: 1- A. Alloying two metals
- B. Coating the surface with less reactive metal
- C. Painting the surface with a dye
- D. All
Explanation: Alloying allows for interactions between metals, which leads to the formation of a protective layer surrounding the metal.
Correct answer: All- A. Group number
- B. Atomic size
- C. Atomic mass
- D. Physical state
Explanation: Generally, groups 1, 2, 3, and 4 have oxidation numbers of +1, +2, +3, and +/-4.
Correct answer: Group number- A. Cl- + I2 -> Cl2 + 2I-
- B. Cu + Zn2+ -> Cu2+ + Zn
- C. Mg + 2H + -> Mg2+ + H2
- D. 2Au + 6H+ -> 2Au3+ + 3 H2
Explanation: For a redox reaction to be feasible, the emf of it must be positive. (NOTE: When calculating emf, you take the voltage of each half…
Correct answer: Mg + 2H + -> Mg2+ + H2