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

In partnership with Revision Ninja

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.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

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 is the balanced equation for Fe2+ reacting with MnO4- in acid solution?

    • Fe2+ + MnO4- -> Fe3+ + MnO2
    • Fe2+ + 2MnO4- -> Fe3+ + 2Mn2+ + O2
    • 5Fe2+ + MnO4- + 4H+ -> 5Fe3+ + Mn2+ + 2H2O
    • 5Fe2+ + MnO4- + 8H+ -> 5Fe3+ + Mn2+ + 4H2O

  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 separate indicator needed in a titration of Fe2+ with acidified KMnO4?

    • MnO4- is purple and is reduced to colourless Mn2+, so the endpoint is seen from the first excess of purple colour
    • Iron(II) changes colour to show the endpoint
    • MnO4- is colourless and Fe2+ is purple
    • The reaction produces a precipitate that marks the endpoint

  14. Which factor influences the redox potential for a transition metal ion changing to a lower oxidation state?

    • pH and the ligand present
    • Only the volume of the titration flask
    • Only the colour of the solution
    • Only the temperature of the room

  15. Which change is a reduction in a redox titration?

    • Mn in MnO4- going from +7 to +2
    • Fe2+ going to Fe3+
    • C in C2O4^2- going to CO2
    • Hydrogen in H2O going to H+

  16. Which statement about the redox titration of hydrogen peroxide with manganate(VII) is correct?

    • H2O2 is always reduced to oxygen gas without any change
    • The method only measures the mass of sodium chloride
    • The method can find the concentration of H2O2 in hair bleach
    • Manganate(VII) is reduced by H2O2 to MnO2 only

  17. Which quantity can be found by a redox titration of iron(II) with manganate(VII)?

    • The density of iron metal
    • The mass of iron in an iron tablet
    • The melting point of iron
    • The boiling point of the solution

  18. Why does the reduction of vanadate(V) by zinc in acid produce a sequence of different colours?

    • Vanadium is colourless in every oxidation state
    • The acid changes the colour of vanadium metal only
    • Zinc reacts to form a different coloured oxide at each step
    • Each lower oxidation state of vanadium absorbs a different wavelength of visible light, so the colour changes

  19. Explain why the redox potential of the Fe3+/Fe2+ couple changes when the ligand is changed.

    • The ligand removes all electrons from the iron ion
    • The ligand is oxidised instead of the iron ion
    • The ligand stabilises one oxidation state more strongly, which shifts the electrode potential
    • The ligand has no effect on electrode potentials

  20. Which equation shows that Cu2+ is reduced in a reaction with iodide?

    • Cu2+ + Zn -> Zn2+ + Cu only
    • I- -> I2 + e-
    • 2Cu2+ + 4I- -> 2CuI + I2
    • Cu2+ + 2e- -> Cu+ + 2e-

All AQA Chemistry quizzes