Redox Reactions

Redox Reactions MDCAT MCQs with answers

9 past paper MCQs on Redox Reactions, from the Electrochemistry unit of MDCAT Chemistry. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

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1.An electrochemical cell is based upon which reaction? (MDCAT 2022)

  1. acid-base reaction
  2. redox reaction
  3. nuclear reaction
  4. neutralization reaction
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Correct answer: (b) redox reaction

The cell works by separating the oxidation and the reduction, so the electrons travel through the external circuit.

2.Which of the following situations most clearly demonstrates a key characteristic of a Redox reaction? (UHS MDCAT 2025)

  1. Water boiling to steam
  2. Hydrogen gas reacting with chlorine to form hydrogen chloride gas
  3. Sodium chloride dissolving in water
  4. Ethanol evaporating at room temperature
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Correct answer: (b) Hydrogen gas reacting with chlorine to form hydrogen chloride gas

Hydrogen loses electrons to chlorine; the other three changes are physical.

3.Placing a rod of iron metal in a solution of CuSO4: (NUMS MDCAT 2024)

  1. Cu will be deposited
  2. Fe is precipitated out
  3. Cu and Fe both dissolve
  4. No reaction taken place
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Correct answer: (a) Cu will be deposited

Iron is above copper in the reactivity series, so it displaces copper from the solution.

4.Q.90 An electrochemical cell is based upon which reaction? (UHS MDCAT 2023)

  1. Acid-base reaction
  2. Redox reaction
  3. Nuclear reaction
  4. Neutralization reaction
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Correct answer: (b) Redox reaction

An electrochemical cell draws its emf from a redox reaction split between two electrodes.

5.The branch of science which deals with the conversion of electrical energy to chemical energy and vice versa is called: (SZABMU MDCAT 2023)

  1. Electrochemistry
  2. Thermochemistry
  3. Stereochemistry
  4. Biochemistry
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Correct answer: (a) Electrochemistry

That is electrochemistry.

6.Fe is precipitated out when Mg strip is dipped in (PMC MDCAT 2022)

  1. FeSO4 solution
  2. CuSO4 Solution
  3. MgSO4 Solution
  4. H2SO4 solution
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Correct answer: (a) FeSO4 solution

Magnesium is above iron in the reactivity series, so it displaces iron from the solution.

7.Which of the following substances is the strongest reducing agent? (PMC MDCAT 2022)

  1. Cl2
  2. Cl-
  3. Br2
  4. Br-
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Correct answer: (d) Br-

A reducing agent gives up electrons, and the bromide ion parts with one most readily here.

8.A galvanic cell is setup (PMC MDCAT 2022)

  1. When a less reactive metal contacts a more reactive metal via an electrolyte
  2. When two reactive metals contact via an electrolyte
  3. When two reactive metals are placed in any solutiin
  4. When two metals come In direct contact
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Correct answer: (a) When a less reactive metal contacts a more reactive metal via an electrolyte

A galvanic cell needs two metals of different reactivity joined through an electrolyte.

9.Keeping in mind the electrode potential, which one of the following reactions is feasible? (UHS MDCAT 2015)

  1. Zn+2 + Cu Cu+2 + Zn
  2. Zn + MgSO4
  3. Fe + CuSO4 ZnSO4 + Mg FeSO4 + Cu
  4. Cd + MgSO4 CdSO4 + Mg
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Correct answer: (c) Fe + CuSO4 ZnSO4 + Mg FeSO4 + Cu

Iron stands above copper in the series, so it displaces copper from the sulphate.

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