Syllabus Edition

First teaching 2023

First exams 2025

|

Proton Transfer Reactions (SL IB Chemistry)

Exam Questions

5 hours90 questions
11 mark

Using your knowledge of the Brønsted-Lowry theory, which of the following correctly describes ammonia?

  • neutral

  • acid

  • base

  • amphoteric

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21 mark

In the Brønsted–Lowry theory of acids and bases, the difference between a conjugate acid and its conjugate base is the presence of which of the following?

  • a positive charge

  • a pair of electrons

  • a proton

  • a hydrogen atom

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31 mark

Which of the following ions or compounds is amphiprotic?

  • P4O10

  • PO43−

  • HCO3

  • Al2O3

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41 mark

In the following reaction, identify which two species are acting as Brønsted–Lowry acids

H3PO4 (aq) + OH (aq)  ⇋ H2PO4 (aq) + H2O (l)

  • H2PO4 (aq) and OH (aq)

  • H3PO4 (aq) and H2PO4 (aq)

  • H2PO4 (aq) and H2O (l)

  • H3PO4 (aq) and H2O (l)

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51 mark

Potassium hydrogen carbonate reacts vigorously with dilute sulfuric acid. Identify the correct formulas of the substances produced in the reaction

  • K2SO4 + H2O + CO2

  • K2SO4 + CO2

  • KSO4 + H2O + CO2

  • KSO4 + H2CO3

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61 mark

Copper(II) sulfate can be made by the reaction between dilute sulfuric acid and which of the following?

  1. Cu
  2. CuO
  3. CuCO3
  • I and II only

  • I and III only

  • II and III only

  • I, II and III

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71 mark

Which statement is correct for the following equation?

HSO4- (aq) + OH- (aq) ⇌ SO4- (aq) + H2O (l)

  • OH- and H2O are an acid and conjugate base pair

  • SO4- is acting as Brønsted–Lowry acid

  • HSO4- and SO4- are a base and conjugate acid pair

  • OH- and H2O are a base and conjugate acid pair

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81 mark

Which row shows the correct acid and base needed to make the salt specified? 

 

Acid

Base

Salt

A

NaHCO3

SO2

Na2SO4

B

HNO3

SO3

(NH4)2SO4

C

H2SO4

ZnO

ZnSO3

D

H2SO4

NH4OH

(NH4)2SO4

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    91 mark

    Which is a conjugate acid-base pair?

    HCO3- (aq) + H2O (l)  ⇌ CO32- (aq) + H3O+ (aq)

    • HCO3- / H3O+

    • HCO3- / CO32- 

    • H2O / CO32- 

    • HCO3- / H2O

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    101 mark

    Which coefficients balance the following acid-base equation?

    Al(OH)3 (s) + HNO3 (aq)  ⇌ Al(NO3)3 (aq) + H2O (l)

    A

    3

    1

    3

    1

    B

    2

    2

    1

    3

    C

    1

    3

    1

    3

    D

    1

    2

    1

    2

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      111 mark

      Four 1.0 M solutions of HCl, NH3, NaOH and CH3COOH have been mislabelled, but a student has a pH meter to test the pH of the solutions. Arrange the solutions in order of increasing pH:

      • HCl (aq) < NH3 (aq) < NaOH (aq) < CH3COOH (aq)

      • CH3COOH (aq) < HCl (aq) < NH3 (aq) < NaOH (aq)

      • HCl (aq) < CH3COOH (aq) < NH3 (aq) < NaOH (aq)

      • NaOH (aq) < NH3 (aq) < CH3COOH (aq) < HCl (aq)

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      121 mark

      Below are four statements about acid and bases. Which is the correct one?

      • Strong acids are good proton donors and have weak conjugate bases.

      • Strong bases are good proton donors and have weak conjugate acids.

      • Weak acids are poor proton acceptors and have strong conjugate bases.

      • Strong acids are good proton donors and have strong conjugate bases.

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      131 mark

      Which statement is correct about the action of weak acids and their conductivity?

      • Weak acids are proton donors and their solutions are good conductors.

      • Weak acids are proton donors and their solutions are poor conductors.

      • Weak acids are proton acceptors and their solutions are good conductors.

      • Weak acids are proton acceptors and their solutions are good conductors.

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      141 mark

      34.3 cm3 of 0.125 mol dm-3 sodium hydroxide solution reacts with 26.0 cm3 of sulfuric acid. What is the concentration of the acid?

      • 0.16 mol dm–3

      • 0.33 mol dm–3

      • 0.08 mol dm–3

      • 3.03 mol dm–3

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      151 mark

      Which of the following is true about weak acids?

      1. They are poor conductors of electricity
      2. They have a high pH
      3. They react with carbonates to produce carbon dioxide
      • I and II only

      • I and III only

      • II and III only

      • I, II and III

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      161 mark

      Which is true about 1.0 mol dm-3 solutions of weak and strong acids?

      • Magnesium will react with strong acids but not weak acids

      • Fewer moles of base are needed to neutralise weak acids

      • Sodium carbonate reacts more slowly with weak acids

      • Weak acids have a lower pH than strong acids

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      171 mark

      Two beakers contain solutions of hydrochloric acid at pH = 2 and pH = 4. How does the concentration of hydrogen ions compare in the two beakers?

      • Twice as large

      • Half as much

      • begin mathsize 16px style 1 over 10 end style of the value

      • begin mathsize 16px style 1 over 100 end style of the value

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      181 mark

      A sample of acid rain water is tested and found to be pH 4. How does its hydrogen ion concentration compare to pure water? 

      • 1000 times more concentrated

      • 3 times more concentrated

      • 1000 times less concentrated

      • 3 times less concentrated

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      19
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      1 mark

      Which type of titration is indicated by the following pH curve?

      PH curve

      • Strong acid - strong base

      • Weak acid - weak base

      • Strong acid - weak base

      • Weak acid - strong base

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      11 mark

      The typical reactions of dilute acids include them being able to react with

      1. NaHCO3
      2. Mg
      3. Cu
      • I and II only

      • I and III only

      • II and III only

      • I, II and III

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      21 mark

      The following reaction occurs between concentrated sulfuric and nitric acids.

      H2SO4 + HNO3 ⇋  H2NO3+ + HSO4-

      Identify the two species which are acting as Brønsted–Lowry bases.

      • H2NO3+ and HSO4-

      • HNO3 and H2NO3+

      • H2SO4 and HSO4- 

      • HNO3 and HSO4-

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      31 mark

      What role does each species play in the equilibrium below according to Brønsted-Lowry theory?

      CH3COOH + HCl  ⇌ CH3COOH2+ + Cl-

       

      CH3COOH

      HCl

      CH3COOH2+

      Cl-

      A

      acid

      base

      base

      acid

      B

      acid

      base

      acid

      base

      C

      base

      acid

      base

      acid

      D

      base

      acid

      acid

      base

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        41 mark

        Perbromic acid, HBrO4 , is an example of a strong acid when dissolved in water. What is true about perbromic acid?

        • HBrO4 is largely found as molecules in the solution

        • HBrO4 solution reacts only with strong bases

        • HBrO4 is fully dissociated in solution

        • HBrO4 has a pH greater than 7

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        51 mark

        Potassium hydrogenphosphate has the formula K2HPO4 . What is the conjugate base of this compound?

        • H2PO4-

        • KHPO42-

        • PO43-

        • KH2PO4

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        61 mark

        For the equilibrium equation shown, which species are Brønsted-Lowry acids?

        H3NSO3 (aq) + 2NH3 (aq) ⇌ HNSO32- (aq) + 2NH4+ (aq)

        • NH4+ and NH3

        • NH4+ and HNSO32-

        • H3NSO3 and HNSO32-

        • H3NSO3 and NH4+

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        71 mark

        Which would be formed when calcium oxide reacts with hydrochloric acid ?

        • Calcium chloride and carbon dioxide

        • Calcium chloride, hydrogen gas and water

        • Calcium, hydrogen gas and water

        • Calcium chloride and water

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        81 mark

         What is the sum of the coefficients when the following acid-base equation is balanced?

        _HNO3 (aq) + _Mg(HCO3)2 (s) →  _Mg(NO3)2 (aq) + _H2O (l) + _CO2  (g)

        • 5

        • 6

        • 7

        • 8

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        91 mark

        Which oxides react with calcium oxide?

        1. SO2
        2. NO2
        3. K2O
        • I and II only

        • I and III only

        • II and III only

        • I, II and III

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        101 mark

        Which row correctly describes the reaction specified?

         

        Reaction

        Energy change

        A

        metal displacement

        endothermic

        B

        neutralisation

        exothermic

        C

        combustion

        endothermic

        D

        melting ice

        exothermic

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          111 mark

          Determine which of the following solutions would be basic at 25 °C?

          Kw = 1.0 × 10−14 mol2 dm-6

          • [H+] = 1.0 × 10−2 mol dm−3

          • [OH] = 1.0 × 10−12 mol dm−3

          • solution of pH = 5.00

          • [H3O+] = 1.0 × 10−12 mol dm−3

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          121 mark

          Carbon dioxide reacts with water to form carbonic acid which can be represented in the following equation

          CO2(g)  +  H2O(l)  ⇋  H+(aq)  +  HCO3(aq)

          If the pressure is raised, what will happen to the position of equilibrium and the pH?

          • The equilibrium shifts to the right and pH increases

          • The equilibrium shifts to the right and pH decreases

          • The equilibrium shifts to the left and pH increases

          • The equilibrium shifts to the left and pH decreases

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          131 mark

          When comparing the separate reactions of 0.5 g magnesium metal with equal volumes and concentrations of hydrochloric acid and ethanoic acid you can say that the

          • Hydrochloric acid reacts faster than ethanoic acid as its pH is higher

          • More gas is produced with hydrochloric acid than with ethanoic acid

          • An equal volume of gas is produced with both hydrochloric acid and ethanoic acid.

          • Ethanoic acid reacts more slowly than hydrochloric acid because its pH is lower 

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          141 mark

          A beaker contains 50 cm3 of sodium hydroxide solution and its pH is measured as 11.
          If 450 cm3 of water is added to the beaker, what will be the new pH of the solution?

          • 3

          • 9

          • 10

          • 11

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          151 mark

          In the table below are the formulae of some acids and bases. Which row shows only weak acids and weak bases?

          A

          CH3NH2

          Ba(OH)2

          HCOOH

          B

          CH3CH2COOH

          C6H5NH2

          HCOOH

          C

          NH3

          HNO3

          CH3CH2COOH

          D

          NH3

          KOH

          H2CO3

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            161 mark

            Three solutions of hydrochloric acid of different concentrations are shown below

            X.   0.100 mol dm-3

            Y.   0.001 mol dm-3

            Z.   0.010 mol dm-3

            If these solutions are arranged from lowest to highest pH, then the order is  

            • X﹤ Y Z

            • X﹤ Z Y

            • Y﹤ X Z

            • Y﹤ Z X

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            171 mark

            Which of the following statements is correct? 

            • As temperature increases, the pH value of pure water decreases

            • As temperature decreases, the pH value of pure water decreases

            • The pH of water is unaffected by temperature 

            • Pure water is not neutral 

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            181 mark

            Equal volumes of hydrochloric acid of different concentrations are added to four beakers, A, B, C and D. Equal volumes of 1.0 mol dm-3 sodium hydroxide are then added to the beakers and the pH is measured.

            Beaker

            A

            B

            C

            D

            pH

            1

            5

            7

            13

            Which beaker contains the most concentrated solution of hydrochloric acid?

            • Beaker A

            • Beaker B

            • Beaker C

            • Beaker D

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            11 mark

            Some species may be classified as amphiprotic, some as amphoteric and some as both. Which of the following applies to HPO42−?

            • Amphiprotic but not amphoteric

            • Amphoteric but not amphiprotic

            • Amphiprotic and amphoteric

            • Neither amphiprotic nor amphoteric

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            21 mark

            The aromatic compound phenol, C6H5OH, behaves as a weak acid, due the presence of a hydroxyl group on the benzene ring. What is the correct formula of the conjugate base formed when phenol dissociates?

            • C6H4--OH 

            • C6H5-OH2+

            • C6H5-O-

            • C6H6+-OH 

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            31 mark

            What is the sum of the coefficients when the following acid-base equation is balanced?

            _Al2(CO3)3 (s) + _HNO3 (aq)  ⇌ _Al(NO3)3 (aq) + _H2O (l) +  _CO2 (g)

            • 6

            • 7

            • 14

            • 15

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            41 mark

            Which of the following substances can be used to prepare magnesium sulfate by a neutralization reaction with dilute sulfuric acid?

            1. Mg
            2. MgO
            3. MgCO3
            • I and II only

            • I and III only

            • II and III only

            • I, II and III

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            51 mark

            Phosphoric acid is a polyprotic acid and can produce amphiprotic species when it dissociates. Which of the following species is amphiprotic?

            1. HPO42−
            2. H2PO4
            3. PO43−
            • I and II only

            • I and III only

            • II and III only

            • I, II and III

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            61 mark

            Use the following reactions to answer the question below:

            H2O (l) + F- (aq) ⇌ HF (aq) + OH- (aq)

            H2O (l) + HNO3 (aq) → H3O+ (aq) + NO3- (aq)

            H2O (l) + CO2 (g) ⇌ H2CO3 (aq)

            H2O (aq) +  NH3 (aq) ⇌ NH4OH (aq) 

            Which of the following statements is true?

            • HNO3 and H2O both act as acids once

            • H2O is shown acting as a Bronsted-Lowry acid only

            • H2O reacts as an acid twice

            • H2O is shown as a diprotic acid

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            71 mark

            Which species are Bronsted-Lowry acids in the reaction shown?

            H2PO4(aq) + CN- (aq) ⇌  HCN (aq)  + HPO42− (aq)

            • HCN and H2PO4

            • HCN and CN-

            • H2PO4and HPO42−

            • HCN and HPO42−

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            81 mark

            Which of the following solutions will react with a strip magnesium ribbon?

            • Sodium hydrogencarbonate

            • Sodium hydrogensulfate

            • Ammonia

            • Limewater

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            91 mark

            Which substance reacts with ammonia but is not a Brønsted–Lowry acid?

            • HCl

            • CH3COOH

            • BF3

            • CF3COOH

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            101 mark

            Which of the following statements is incorrect about  0.01 mol dm–3 CH3COOH?

            • the pH = 2

            • [H+] << 0.01 mol dm–3

            • [CH3COO] is approximately equal to [H+]

            • CH3COOH is partially ionized

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            111 mark

            Two flasks contain two different acids labelled as HA and HB. A student measures the pH of each flask, and finds that they are pH 1 and pH 3 respectively. Which of the following statements is true?

            • HA is a stronger acid than HB

            • HB is a stronger acid than HA

            • The [H3O+] in the solution of HB is 3 times greater than the [H3O+] in the solution of HA.

            • The [H3O+] in the solution of HA is 100 times greater than the [H3O+]  in the solution of HB.

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            121 mark

            Which of the following solutions will have the largest amount of H+ ions in moles?

            • 20 cm3 of 2.0 mol dm−3 sulfuric acid

            • 10 cm3 of 3.0 mol dm−3 nitric acid

            • 80 cm3 of 0.5 mol dm−3 hydrochloric acid

            • 40 cm3 of 1.0 mol dm−3 ethanoic acid

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            131 mark

            If the pH of two acids, X and Y, are pH 1 and pH 2 respectively, which of the following is true?

            1. X and Y could be strong or weak acids
            2. The concentration of [H+] ions in X is higher than in Y
            3. Acid X is stronger than acid Y
            • I and II only

            • I and III only

            • II and III only

            • I, II and III

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            141 mark

            A student has two flasks containing 150 cm3 of nitric acid, HNO3(aq) and ethanoic acid, CH3COOH(aq). She writes the following three statements in her notebook about the acids. Which of them are correct?

            1. HNO3 dissociates more than CH3COOH
            2. HNO3 conducts electricity better than CH3COOH
            3. more NaOH can be neutralized with HNO3 than CH3COOH
            • I and II only

            • I and III only

            • II and III only

            • I, II and III

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            151 mark

            In a titration, the equivalence point is reached when 23.70 cm3 of 0.02 mol dm-3 potassium hydroxide reacts with 0.03 mol dm-3 of sulfuric acid. What volume of acid is needed?

            • 7.9 cm3

            • 31.65 cm3

            • 15.80 cm3

            • 17.78 cm3

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            161 mark

            Acid rain can be up to 50 times more acidic than normal rain, which has a pH around 5.5. What is the approximate concentration of H+ in acid rain?

            • 2.50 size 16px cross times10-3 mol dm-3 

            • 2.50 size 16px cross times 10-4 mol dm-3 

            • 2.50 size 16px cross times 10-5 mol dm-3 

            • 50.0 begin mathsize 16px style cross times end style 10-4 mol dm-3 

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            171 mark

            Which is true about the hydrogensulfate ion, HSO4-, found in acid rain?

            1. It is amphiprotic
            2. It is amphoteric
            3. Sulfur is in its highest oxidation state
            • I and II only

            • I and III only

            • II and III only

            • I, II and III

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