Transition Metal Reactions (Edexcel International A Level Chemistry)

Exam Questions

42 mins11 questions
11 mark

Aqueous ammonia is added drop by drop to a solution of cobalt(II) chloride, CoCl2(aq), until in excess.

What would be the sequence of observations?

  • blue solution → pink precipitate → dark blue solution

  • pink solution → blue precipitate

  • blue solution → pink precipitate

  • pink solution → blue precipitate → yellow‐brown solution

Did this page help you?

11 mark

When an alkene is added to a solution of potassium manganate(VII), the purple solution turns colourless.

In terms of electron transfer and oxidation number, how does the manganese change in this reaction?

      Electron transfer Oxidation number
  A gains electrons increases
  B gains electrons decreases
  C loses electrons increases
  D loses electrons decreases

    Did this page help you?

    21 mark

    Aqueous sodium hydroxide was added to aqueous iron(II) sulfate and the mixture allowed to stand.

    What would be observed?

        Observations
        Immediately after adding
    sodium hydroxide
    After standing
    A brown precipitate no change
    B green precipitate no change
    C brown precipitate precipitate turns green
    D green precipitate precipitate turns brown 

      Did this page help you?

      31 mark

      Which of the following is not true of the reactions occurring in the catalytic converter fitted to a car exhaust?

      • they involve heterogeneous catalysis

      • carbon monoxide is adsorbed onto the surface of the catalyst

      • nitrogen is desorbed from the surface of the catalyst

      • the products cause no harm to the environment

      Did this page help you?

      41 mark

      When aqueous ammonia is added to an aqueous solution of zinc sulfate, a white precipitate forms which dissolves in excess ammonia to give a colourless solution.

      What types of reaction are occurring?

          Type of reaction
          Formation of white
      precipitate
      Formation of colourless
      solution
      A deprotonation ligand exchange
      B deprotonation deprotonation
      C ligand exchange deprotonation
      D ligand exchange ligand exchange

        Did this page help you?

        51 mark

        The reaction of ethanedioate ions, C2O42–, with manganate(VII) ions, MnO4, in acidic solution involves autocatalysis.

        2MnO4 + 16H++ 5C2O42– → 2Mn2+ + 10CO2 + 8H2O

        The catalyst in this reaction is

        • Mnstraight O subscript 4 superscript minus

        • H+

        • Mn2+

        • CO2

        Did this page help you?

        61 mark

        Iodide ions are oxidised by peroxodisulfate ions in aqueous solution.

        2 straight I to the power of minus space plus space straight S subscript 2 straight O subscript 8 superscript 2 minus end superscript space rightwards arrow space straight I subscript 2 space plus space 2 SO subscript 4 superscript 2 minus end superscript

        This reaction is catalysed by adding Fe2+ ions to the solution.
        This catalysis is effective because

        • Fe2+ reacts with iodide ions and with peroxodisulfate ions

        • Fe2+ has many electrons in its outermost subshells

        • Fe2+ has many active sites on which the reaction can occur

        • Fe2+ is readily oxidised to Fe3+ which is then reduced to Fe2+

        Did this page help you?

        11 mark

        Iodide ions, I, are oxidised by peroxodisulfate(VI) ions, S2straight O subscript 8 superscript 2 minus end superscript.

        2I(aq) + S2straight O subscript 8 superscript 2 minus end superscript(aq) → I2(aq) + 2Sbegin mathsize 16px style O subscript 4 to the power of 2 minus sign end style(aq)

        Which of the following statements is true of this reaction?

        • both Fe2+(aq) and Fe3+(aq) catalyse the reaction

        • Fe2+(aq) catalyses the reaction but Fe3+(aq) does not

        • Fe3+(aq) catalyses the reaction but Fe2+(aq) does not

        • neither Fe2+(aq) nor Fe3+(aq) catalyses the reaction

        Did this page help you?