Lesson 3.1.11.1

3.1.11.1 Electrode potentials and cells Quiz: AQA Chemistry, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.1.11.1, Electrode potentials and cells: 20 multiple choice questions for the AQA Chemistry (7405), Unit 1: Physical chemistry, written with Revision Ninja.

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The 20 questions

  1. Standard electrode potential, E-standard, is measured under which conditions?

    • 298 K, 1 atm and 0.10 mol dm^-3 solutions of ions
    • 373 K, 100 kPa and 2.00 mol dm^-3 solutions of ions
    • 273 K, 101 kPa and 0.10 mol dm^-3 solutions of ions
    • 298 K, 100 kPa and 1.00 mol dm^-3 solutions of ions

  2. By definition, what is the electrode potential of the standard hydrogen electrode?

    • +0.34 V
    • -0.76 V
    • +1.00 V
    • 0.00 V

  3. Why are electrode potentials measured against the standard hydrogen electrode?

    • The hydrogen electrode is the only electrode that can be used in a cell at all
    • The hydrogen electrode always has the highest potential, which makes all others easy to compare
    • Only potential differences can be measured, so a reference electrode with a defined value is needed
    • Hydrogen gas is the only substance that gives reproducible potentials with any solution

  4. Using standard electrode potentials Zn2+/Zn = -0.76 V and Cu2+/Cu = +0.34 V, what is the EMF of the cell Zn|Zn2+||Cu2+|Cu?

    • +0.42 V
    • -1.10 V
    • +1.10 V
    • +0.76 V

  5. Given that Zn2+/Zn is -0.76 V and Cu2+/Cu is +0.34 V, will zinc metal reduce copper(II) ions in solution?

    • No, because zinc metal cannot lose electrons in any aqueous solution
    • No, because copper has the more negative standard electrode potential and is the stronger reducing agent
    • Yes, because copper(II) ions are reduced by any metal, whatever the potentials
    • Yes, because zinc has the more negative standard electrode potential and is the stronger reducing agent

  6. Using Fe2+/Fe = -0.44 V and Cu2+/Cu = +0.34 V, what is the EMF of a cell with Fe and Cu2+ as the reacting pair, and does the reaction occur?

    • -0.78 V, so copper(II) ions do not oxidise iron
    • +0.78 V, so copper(II) ions oxidise iron
    • +0.10 V, so copper(II) ions do not oxidise iron
    • +0.78 V, so iron oxidises copper metal

  7. With Ag+/Ag = +0.80 V and Zn2+/Zn = -0.76 V, what is the EMF of the cell Zn|Zn2+||Ag+|Ag?

    • +1.56 V
    • -1.56 V
    • +0.04 V
    • +1.04 V

  8. By IUPAC convention, how are the standard electrode potentials normally written as half-equations?

    • As oxidation half-equations, with electrons on the right-hand side
    • As overall redox equations, with the reducing agent on the left
    • As reduction half-equations, with electrons on the left-hand side
    • As half-equations written with the hydrogen electrode always on the left

  9. In the conventional representation of a cell, where is the anode, the site of oxidation, placed?

    • On the left-hand side of the cell notation
    • On the right-hand side of the cell notation
    • Above the cell notation as a separate label
    • In the middle, between the two vertical lines

  10. Which is the correct conventional representation of a cell made from magnesium and silver, with Mg as the negative electrode?

    • Mg||Mg2+|Ag+||Ag
    • Mg|Mg2+||Ag+|Ag
    • Mg2+|Mg||Ag|Ag+
    • Ag|Ag+||Mg2+|Mg

  11. Using Cl2/Cl- = +1.36 V and Fe3+/Fe2+ = +0.77 V, what is the EMF of a cell made from these two couples?

    • +0.59 V
    • +0.77 V
    • +2.13 V
    • -0.59 V

  12. Which species is the strongest oxidising agent among Cl2/Cl- = +1.36 V, Ag+/Ag = +0.80 V and I2/I- = +0.54 V?

    • Ag+, because it is the most common of the three
    • I-, because it has the most negative electrode potential
    • I2, because it has the lowest electrode potential
    • Cl2, because it has the most positive electrode potential

  13. Which species is the strongest reducing agent among Li+/Li = -3.04 V, Mg2+/Mg = -2.37 V and Fe2+/Fe = -0.44 V?

    • Mg2+, because it is the most positive of the ions
    • Li, because it has the most negative electrode potential
    • Fe2+, because it is the most reactive of the three
    • Fe, because it has the most positive electrode potential

  14. A solution has ion concentrations different from 1.00 mol dm^-3. What happens to the electrode potential, E, compared with E-standard?

    • E changes from E-standard, because the value depends on the concentration of the ions
    • E is always zero, because only standard conditions give a measurable potential
    • E is always identical to E-standard, because concentration has no effect at all
    • E is always double E-standard, because the concentration is halved

  15. Why must the voltmeter used to measure the EMF of a cell have a high resistance?

    • It stops all electron flow, which gives a zero reading that confirms the cell is working
    • It draws very little current, so the reading is close to the true EMF of the cell
    • It converts the cell into a fuel cell, so the reading is taken under different conditions
    • It increases the current drawn, so the cell reaction is faster and more accurate

  16. Fe3+/Fe2+ = +0.77 V and I2/I- = +0.54 V. Will Fe3+ oxidise I- to I2, and what is the EMF?

    • No, with an EMF of +0.23 V
    • Yes, with an EMF of +1.31 V
    • No, with an EMF of -0.23 V
    • Yes, with an EMF of +0.23 V

  17. Mg|Mg2+||Cu2+|Cu uses Mg2+/Mg = -2.37 V and Cu2+/Cu = +0.34 V. What is the EMF of this cell?

    • +0.34 V
    • -2.71 V
    • +2.71 V
    • +2.03 V

  18. Which species is oxidised in a cell in which the more negative half-cell is the anode?

    • Neither species, because only the salt bridge is oxidised
    • The species in the half-cell with the more positive electrode potential
    • The species in the half-cell with the more negative electrode potential
    • Both species equally, because the EMF is shared between them

  19. The cell Zn|Zn2+||Cu2+|Cu gives EMF +1.10 V. What is the EMF of the reverse cell, Cu|Cu2+||Zn2+|Zn, and what does its sign mean?

    • +1.10 V, so the reverse cell is spontaneous as written
    • 0.00 V, so neither cell can ever be made to work
    • -1.10 V, so the reverse cell is not spontaneous as written
    • -1.10 V, so the reverse cell is the more spontaneous of the two

  20. Why is a standard electrode potential defined as a reduction potential?

    • So that all electrode potentials are compared on one consistent convention, with the same sign rules
    • Because oxidation reactions cannot be measured using any voltmeter
    • Because only reduction reactions release electrons into the external circuit
    • Because reduction always occurs at the standard hydrogen electrode, so only reductions are needed

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