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DP IB Chemistry: SL

Topic Questions

Home / IB / Chemistry: SL / DP / Topic Questions / 8. Acids & Bases / 8.1 Theories & Reactions of Acids & Bases / Structured Questions: Paper 2


8.1 Theories & Reactions of Acids & Bases

Question 1a

Marks: 2
a)
Explain why an ammonium ion can not behave as a Brønsted-Lowry base.
[2]
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    Question 1b

    Marks: 2
    b)
    State and explain the acid-base character of aqueous ammonia at 298 K.
    [2]
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      Question 1c

      Marks: 2
      c)
      Acids can be classed as monoprotic, diprotic and triprotic. Sulfuric acid is a diprotic acid. 

      i)
      State the equation for the first ionisation step of sulfuric acid, including state symbols.

      ii)
      Label the conjugate acid and base pairs in your answer to part i).
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        Question 1d

        Marks: 1
        d)
        The second ionisation step is for the ionisation of sulfuric acid is as follows.

        HSO4- (aq) + H2O (aq) ⇌ SO42- (aq) + H3O+ (aq)


        Suggest why the second
        ionisation step reaches equilibrium.

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          Question 2a

          Marks: 2
          a)
          Sodium hydrogen carbonate solution, NaHCO3 (aq) , can act as an amphiprotic species. State the equation for the reaction fo NaHCO3 (aq) with the following compounds:

          i)
          Sodium hydroxide solution. 
          [1]

          ii)
          Hydrochloric acid. 
          [1]

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            Key Concepts
            Amphiprotic Species

            Question 2b

            Marks: 3
            b)
            Using your answer to part a) i) and ii), explain why NaHCOis amphiprotic. 
            [3]
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              Key Concepts
              Amphiprotic Species

              Question 2c

              Marks: 3
              c)
              Phosphine is usually prepared by heating white phosphorus, one of the allotropes of phosphorus, with concentrated aqueous sodium hydroxide.

              The equation for the reaction is.

              P4 (s) + 3OH (aq) + 3H2O (l) → PH3 (g) + 3H2PO2 (aq)

              Identify the amphiprotic species in this reaction giving the formulas of both species it is converted to when it behaves in this manner.
              [3]
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                Key Concepts
                Amphiprotic Species

                Question 2d

                Marks: 4
                d)
                1.68 g of white phosphorus was used to make phosphine

                i)
                Calculate the amount, in mol, of white phosphorus used.
                [1]
                ii)
                This phosphorus was reacted with 50.0 cm3 of 3.00 mol dm−3 aqueous sodium hydroxide. Deduce, showing your working, which was the limiting reagent.
                [1]

                iii)
                Determine the excess amount, in mol, of the other reagent.
                [1]

                iv)
                Using section 2 of the data booklet. Determine the volume of phosphine, measured in cm3 at standard temperature and pressure, that was produced.
                [1]


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                  Question 3a

                  Marks: 2
                  a)
                  Oxalic acid, H2C2O, is a weak diprotic acid and can be used in titrations. State the equation for the reaction of oxalic acid with sodium hydroxide. 
                  [2]
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                    Question 3b

                    Marks: 2
                    b)
                    The ionisation of oxalic acid occurs in two steps. State equations for both of these steps. 
                    [2]
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                      Question 3c

                      Marks: 3
                      c)
                      Tartaric acid shown below behaves as a Brønsted-Lowry acid when it reacts with calcium hydroxide, Ca(OH)2. Sketch the structure of the salt formed from this reaction. 

                      8-1-ib-sl-sq-hard-q3c-tartaric-acid
                      [3]
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                        Question 4a

                        Marks: 4

                        Using ionic equations state how HPO42- can behave as an amphiprotic and amphoteric species.

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                          Key Concepts
                          Amphiprotic Species

                          Question 4b

                          Marks: 2

                          Gallium oxide behaves as an amphoteric oxide. State two equations to show how gallium oxide reacts with a strong monoprotic acid and strong base.

                          Reaction with strong monoprotic acid .........................................................................................................................................

                          Reaction with strong base .........................................................................................................................................

                          [2]

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                            Key Concepts
                            Amphiprotic Species

                            Question 4c

                            Marks: 1
                            c)
                            Identify the Br∅nsted-Lowry acids in the following reaction.
                            CH3CH2O- (aq) + H2O (l) rightwards harpoon over leftwards harpoonCH3CH2OH (aq) + OH- (aq)
                            [1]

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