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 2 of 35
- A. X2YZ
- B. XY2Z2
- C. XYZ2
- D. XY2Z
Explanation: A neutral compound must have oxidation numbers summing to zero, and XY2Z2 gives plus 6, then two at minus 2 and two at minus 1, that is 6…
Correct answer: XY2Z2- A. H+1 > Cu+2 > Ag+
- B. H+1 > Ag+ > Cu+2
- C. Ag+ > Cu+2 > H+1
- D. H+1 > Cu+2 > Ag+
Explanation: The more positive the standard electrode potential, the more readily the ion accepts electrons, and the values are plus 0.80 V for silver…
Correct answer: Ag+ > Cu+2 > H+1- A. Water boiling to steam
- B. Hydrogen gas reacting with chlorine to form hydrogen chloride gas
- C. Sodium chloride dissolving in water
- D. Ethanol evaporating at room temperature
Explanation: Hydrogen goes from zero to plus 1 and chlorine from zero to minus 1, so electrons are transferred and oxidation numbers change, which is…
Correct answer: Hydrogen gas reacting with chlorine to form hydrogen chloride gas- A. Transfer of proton
- B. Transfer of electron
- C. Absorption of light
- D. Exchange of ions
Explanation: Oxidation is loss of electrons and reduction is gain, so a redox reaction is defined by electron transfer and by the change in oxidation…
Correct answer: Transfer of electron- A. H+
- B. OH-
- C. H2O
- D. O
Explanation: In the half-reaction method in acidic medium, H2O is added to the side deficient in oxygen atoms, and H+ is then used to balance hydrogen…
Correct answer: H2O- A. according to atom's atomic number.
- B. According to atom's atomic mass.
- C. First we balance Metal than non-metal than Hydrogen than Oxygen.
- D. None of the above
Explanation: For many ordinary equations, a convenient inspection order is to balance metals first, then other nonmetals, followed by hydrogen and…
Correct answer: First we balance Metal than non-metal than Hydrogen than Oxygen.- A. 6
- B. 8
- C. 10
- D. 4
Explanation: Let the equation be aZn + bHNO3 → aZn(NO3)2 + cN2O + dH2O. Hydrogen gives d = b/2, nitrogen gives b = 2a + 2c, and oxygen then gives 3b =…
Correct answer: 10- A. Oxidation
- B. Reduction
- C. Redox
- D. Substitution
Explanation: Reduction takes place at the cathode, meaning the species gains electrons there.
Correct answer: Reduction- A. Reduction
- B. Oxidation
- C. Isomerization
- D. Crackling
Explanation: In the Bosch process, carbon monoxide combines with steam to form carbon dioxide and hydrogen: CO + H2O → CO2 + H2.
Correct answer: Oxidation- A. an anion
- B. a cation
- C. an anion - cation
- D. none of these
Explanation: Loss of an electron leaves a species with more protons than electrons, giving it a net positive charge.
Correct answer: a cation- A. N2O
- B. NO2
- C. HNO2
- D. HNO3
Explanation: In HNO3, hydrogen is +1 and oxygen contributes 3 x -2 = -6, so nitrogen must be +5: +1 + N - 6 = 0, giving N = +5.
Correct answer: HNO3- A. Number of electrons gained
- B. Number of electrons lost
- C. Apparent charge in compound
- D. Its vacancies
Explanation: Oxidation state is the apparent charge assigned to an atom when bonding electrons are treated as belonging to the more electronegative…
Correct answer: Apparent charge in compound- A. 7
- B. 6
- C. -7
- D. -6
Explanation: Let the oxidation number of each chromium atom be x: 2(+1) + 2x + 7(-2) = 0. Thus 2x - 12 = 0, so x = +6.
Correct answer: 6- A. valency
- B. coordination number
- C. oxidation number
- D. charge number
Explanation: Oxidation number is the apparent charge assigned to an atom by assuming that bonding electrons belong completely to the more…
Correct answer: oxidation number- A. oxidation
- B. reduction
- C. oxidation-reduction
- D. all of above represent same entity
Explanation: Reduction means a decrease in oxidation number because the species gains electrons or loses its formal positive character.
Correct answer: reduction- A. oxidation
- B. reduction
- C. redox
- D. decomposition
Explanation: Oxidation always occurs at the anode, whether the cell is galvanic or electrolytic; the electrode signs may change, but this reaction rule…
Correct answer: oxidation- A. Oxidation potential
- B. Reduction potential
- C. Redox potential
- D. emf of cell
Explanation: An oxidising agent accepts electrons, so a stronger oxidising agent has a greater tendency to undergo reduction.
Correct answer: Reduction potential- A. to form positive ions
- B. to form negative ions
- C. gain electrons
- D. all are possible
Explanation: A higher standard reduction potential means a greater tendency to gain electrons and be reduced.
Correct answer: to form positive ions- A. N
- B. Cr
- C. S
- D. Mn
Explanation: The highest common oxidation number listed is Mn(+7), as in permanganate, while N commonly reaches +5 and Cr and S commonly reach +6.
Correct answer: Mn- A. Ag
- B. A
- C. Au
- D. Cu
Explanation: Gold is below the other listed metals in the activity series, so metals such as aluminium, copper and silver can displace gold ions from…
Correct answer: Au