Lesson 3.2.5.5

3.2.5.5 Variable oxidation states Quiz: AQA Chemistry, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.2.5.5, Variable oxidation states: 20 multiple choice questions for the AQA Chemistry (7405), Unit 2: Inorganic chemistry, written with Revision Ninja.

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The 20 questions

  1. What is the common oxidation state of vanadium in the vanadate(V) ion?

    • +5
    • +3
    • +2
    • +4

  2. What is the reducing agent used to reduce vanadate(V) ions in acidic solution in the AQA practical?

    • Zinc
    • Potassium iodide
    • Sodium hydroxide
    • Chlorine

  3. Which oxidation states of vanadium are formed when vanadate(V) is reduced by zinc in acidic solution?

    • +5 only
    • 0 and +1
    • +4, +3 and +2
    • +6 and +7

  4. Which reagent is used to distinguish aldehydes from ketones by a silver mirror?

    • Tollens' reagent
    • Dilute sodium hydroxide
    • Aqueous sodium chloride
    • Acidified potassium manganate(VII)

  5. Which species is reduced to metallic silver in the test with Tollens' reagent?

    • Cu2+
    • NH3
    • OH-
    • [Ag(NH3)2]+

  6. In the reaction of Fe2+ with MnO4- in acid, what is the change in oxidation state of manganese?

    • +7 to +2
    • +7 to +6
    • +7 to +4
    • +2 to +7

  7. What molar ratio of Fe2+ to MnO4- reacts in an acidified redox titration?

    • 1 to 1
    • 1 to 5
    • 2 to 5
    • 5 to 1

  8. What is the balanced equation for ethanedioate reacting with manganate(VII) in acid?

    • 2C2O4^2- + MnO4- + 8H+ -> 4CO2 + Mn2+ + 4H2O
    • 5C2O4^2- + 2MnO4- + 16H+ -> 10CO2 + 2Mn2+ + 8H2O
    • C2O4^2- + MnO4- -> CO2 + Mn2+
    • 5C2O4^2- + 2MnO4- + 8H+ -> 10CO2 + 2Mn2+ + 4H2O

  9. A 25.0 cm3 sample of Fe2+ solution is titrated with 0.0200 mol dm-3 KMnO4, using 20.0 cm3 at the endpoint. How many moles of MnO4- are used?

    • 4.00 x 10^-4 mol
    • 2.00 x 10^-3 mol
    • 1.00 x 10^-3 mol
    • 5.00 x 10^-4 mol

  10. Using the answer to the previous question, how many moles of Fe2+ are in the sample titrated with 4.00 x 10^-4 mol of MnO4-?

    • 1.00 x 10^-2 mol
    • 8.00 x 10^-4 mol
    • 4.00 x 10^-4 mol
    • 2.00 x 10^-3 mol

  11. In a titration of ethanedioate with acidified KMnO4, 20.0 cm3 of 0.0200 mol dm-3 KMnO4 is used. How many moles of ethanedioate, C2O4^2-, react?

    • 4.00 x 10^-4 mol
    • 5.00 x 10^-4 mol
    • 2.00 x 10^-3 mol
    • 1.00 x 10^-3 mol

  12. What is the oxidation state of vanadium in the VO2+ ion?

    • +3
    • +2
    • +4
    • +5

  13. Why is no indicator needed when titrating Fe2+ with acidified potassium manganate(VII)?

    • MnO4- is self-indicating
    • Fe2+ changes colour
    • Neutralisation occurs
    • Precipitate forms

  14. Which two factors influence the redox potential of a transition metal ion?

    • pH and ligand
    • Concentration and surface
    • Temperature and mass
    • Pressure and volume

  15. What is the oxidation state change of manganese when MnO4- is reduced?

    • +7 to +2
    • +7 to +4
    • +5 to +2
    • +6 to +3

  16. What practical commercial product can be analysed by redox titration using manganate(VII)?

    • Vinegar
    • Baking powder
    • Hair bleach
    • Table salt

  17. Which commercial product can be analysed by titrating iron(II) with manganate(VII)?

    • Vitamin C tablet
    • Iron tablet
    • Aspirin tablet
    • Antacid tablet

  18. Why does reducing vanadate(V) with zinc cause a series of colour changes?

    • Thermal decomposition
    • Precipitate formation
    • Ligand exchange reactions
    • Variable oxidation states

  19. How do ligands affect the redox potential of a transition metal ion?

    • Increasing activation energy
    • Changing ion charge
    • Selective stabilisation
    • Decreasing solubility

  20. What is the copper-containing product formed when aqueous Cu2+ reacts with iodide ions?

    • Copper(II) iodide
    • Copper oxide
    • Copper(I) iodide
    • Copper metal

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