Syllabus Edition

First teaching 2023

First exams 2025

|

Proton Transfer Reactions (HL IB Chemistry)

Exam Questions

9 hours138 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

      Which is the correct expression for the ionic product of water at 25 ℃ is

      • begin mathsize 16px style K subscript w equals fraction numerator left square bracket H to the power of plus right square bracket left square bracket O H to the power of minus right square bracket over denominator left square bracket H subscript 2 O right square bracket end fraction end style

      • H2O (l) ⇌ H+ (aq) + OH- (aq)

      • Kw = [H+][OH-]

      • 1 x 10-14 mol2 dm-6

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      151 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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      161 mark

      90 cm3 of water is added to 10 cm3 of sulfuric acid with a pH of 2. What is the new pH of the acid?

      • 1

      • 3

      • 5

      • 7

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      171 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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      181 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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      191 mark

      Four solutions, K, L, M and N have the following properties

      K: pH= 8       L: [H+] = 1 x 10-3 mol dm-3 M: pH= 5    N: [H+] = 1 x 10-7 mol dm-3

      What is their correct order of increasing acidity?

      • K < L < M < N

      • N < L < M < K

      • K < N < M < L

      • N < M < L < K

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      201 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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      211 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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      22
      Sme Calculator
      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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      23
      Sme Calculator
      1 mark

      Which mixture cannot act as a buffer?

      • CH3COOH (aq) and CH3COONa (aq) 

      • CH3CH2COOH (aq) and CH3CH2COONa (aq) 

      • HNO3 (aq) and NaOH (aq)

      • NH3 (aq) and NH4Cl (aq) 

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      24
      Sme Calculator
      1 mark

      The hydrolysis of ammonium chloride takes place via the following reaction.

      NH4+ + H2O → H3O+ + NH3

      Which of the following is correct? 

      • The resultant pH is above 7

      • The resultant pH is 7

      • The resultant pH is below 7

      • Ammonium chloride is insoluble

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      25
      Sme Calculator
      1 mark

      Which of the following is the acid dissociation, Ka, constant for ethanoic acid? 

      • CH3COOH 

      • fraction numerator left square bracket CH subscript 3 COO to the power of minus right square bracket left square bracket straight H to the power of plus right square bracket over denominator left square bracket CH subscript 3 COOH right square bracket end fraction

      • fraction numerator left square bracket CH subscript 3 COOH right square bracket over denominator left square bracket CH subscript 3 COO to the power of minus right square bracket left square bracket straight H to the power of plus right square bracket end fraction

      • left square bracket CH subscript 3 COO to the power of minus right square bracket left square bracket straight H to the power of plus right square bracket

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      26
      Sme Calculator
      1 mark

      At the same concentration, which acid would have the lowest pH?

      • C6H5COOH Ka = 6.3 x 10-5 mol dm-3

      • HCOOH Ka = 1.8 x 10-4 mol dm-3

      • HCN Ka = 4.9 x 10-10 mol dm-3

      • CH3CH2COOH Ka = 1.4 x 10-5 mol dm-3

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      27
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      1 mark

      The pKb value of ethylamine is 3.35 at 298 K. What is the value of the pKa ethylammonium ion?

      • 2.99 x 10–14

      • 10.65

      • 4.18

      • 2.24 x 10–10

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      28
      Sme Calculator
      1 mark

      Which of the following is the correct equation to calculate the concentration of hydroxide ions? 

      • K subscript straight w over pOH

      • -log [H+]

      • 14 - pOH

      • 10-pOH

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      29
      Sme Calculator
      1 mark

      Which shows the correct relationship between Kw, Ka and Kb

      • Kw = KaKb

      • Kw = Ka x Kb

      • K subscript w space equals space K subscript a over K subscript b

      • K subscript w space equals space K subscript b over K subscript a

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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

          Calculate the pH of a solution of NaOH of concentration 0.001 mol dm-3

          • 1

          • 3

          • 11

          • 13

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          131 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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          141 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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          151 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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          161 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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            171 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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            181 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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            191 mark

            Which row shows the correct properties of 0.1 mol dm-3 LiOH?

             

            pH

            Electrical conductivity

            Universal indicator colour

            A

            10

            poor

            green

            B

            13

            good

            purple

            C

            10

            poor

            red

            D

            13

            poor

            blue

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              201 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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              211 mark

              Which of the following statements are correct for a titration between 0.10 mol dm-3 propanoic acid and 0.10 mol dm-3 potassium hydroxide? 

              • The equivalence point will be at pH 7

              • The salt formed will hydrolyse to form an acidic salt 

              • The salt formed will be CH3COOK

              • At half equivalence point [CH3CH2COOH (aq)] = [CH3CH2COO- (aq)]

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              221 mark

              Which of the following statements about indicators are correct? 

              1.  The pKa of the indicator is the midpoint of the pH range
              2.  The colour of the indicator depends upon the pH of the solution
              3.  At the end point of a titration [HIn] = [In-]
              • I and II only

              • I and III only 

              • II and III only

              • I, II and III

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              231 mark

              Which statement about buffer solutions is not correct?

              • A buffer resists small changes in pH

              • A buffer can be formed from sodium hydroxide and an excess of ethanoic acid

              • The pH during a titration between a strong acid and weak base changes slowly in the buffer region 

              • When a strong acid is added to a buffer, hydrogen ions react with salt ions 

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              241 mark

              The pH range of four different indicators are:

              Indicator

              pKa

              Methyl orange

              3.7

              Phenolphthalein

              9.6

              Phenol red

              7.9

              Bromothymol blue

              7.0

              Which indicator would be suitable for a titration involving hydrochloric acid and ammonia?

              • Methyl orange

              • Phenolphthalein

              • Phenol red

              • Bromothymol blue

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              251 mark

              The table shows the pKa and Ka values for four acids

              Acid

              pKa

              Ka

              Butanoic Acid

              -

              1.51 x 10-5

              Nitrous acid

              3.1

              -

              Lactic acid

              3.4

              -

              Phenol

              -

              1 x 10-10

                

              Which of the following is the correct order of increasing strength of the acids

              • Phenol < butanoic acid < lactic acid < nitrous acid 

              • Nitrous acid < lactic acid < butanoic acid < phenol

              • Nitrous acid < butanoic acid < phenol < lactic acid

              • Phenol < lactic acid < butanoic acid < nitrous acid

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              261 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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              271 mark

              Which of the following statements about conjugate acid and base pairs are correct?

              I.
              If an acid has a pKa value of 4, its conjugate base will have a pKb value of 10
              II.
              Ka + Kb = Kw
              III.

              The conjugate base for ethanoic acid is CH3COO-

              • I and II only

              • I and III only

              • II and III only

              • I, II and III

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              281 mark

              What is the correct expression to use to determine the pH of butanoic acid with concentration of 0.75 mol dm-3

              The Ka of butanoic acid at 298 K is 1.51 x 10-5 mol dm-3

              • 4.95

              • 2.47

              • 0.12

              • 4.82

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              291 mark

              What is the correct expression for the base dissociation constant, Kb, for propylamine?

              • Kbbegin mathsize 14px style fraction numerator left square bracket C H subscript 3 C H subscript 2 C H subscript 2 N H subscript 3 to the power of plus right square bracket open square brackets O H to the power of minus sign close square brackets over denominator open square brackets C H subscript 3 C H subscript 2 C H subscript 2 N H subscript 2 close square brackets end fraction end style

              • Kbbegin mathsize 14px style fraction numerator left square bracket C H subscript 3 C H subscript 2 C H subscript 2 N H subscript 3 to the power of plus right square bracket open square brackets H subscript 2 O close square brackets over denominator open square brackets C H subscript 3 C H subscript 2 C H subscript 2 N H subscript 2 close square brackets end fraction end style

              • Kbbegin mathsize 14px style fraction numerator left square bracket C H subscript 3 C H subscript 2 C H subscript 2 N H subscript 3 to the power of plus right square bracket open square brackets O H to the power of minus sign close square brackets over denominator open square brackets C H subscript 3 C H subscript 2 C H subscript 2 N H subscript 2 close square brackets open square brackets H subscript 2 O close square brackets end fraction end style

              • Kbbegin mathsize 14px style left square bracket C H subscript 3 C H subscript 2 C H subscript 2 N H subscript 3 to the power of plus right square bracket open square brackets O H to the power of minus sign close square brackets end style

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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

              Which row shows the correct colours for two common indicators used in acid-alkali titrations?

              phenolphthalein

              methyl orange

               

              colour in acid

              colour in alkali

              colour in acid

              colour in alkali

              A

              pink

              colourless

              yellow

              red

              B

              colourless

              pink

              yellow

              red

              C

              pink

              colourless

              red

              yellow

              D

              colourless

              pink

              red

              yellow

               

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                161 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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                171 mark

                What is the number of moles of barium hydroxide in a 100 cm3 solution with a pH of 11 at 25 ℃?

                (Kw = 1.00 x 10-14 mol2 dm-6 at 298 K)

                • 1 begin mathsize 16px style cross times end style 10-11 mol 

                • 1 begin mathsize 16px style cross times end style 10-3 mol

                • 0.5 begin mathsize 16px style cross times end style 10-3 mol

                • 0.5 begin mathsize 16px style cross times end style 10-4 mol

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                181 mark

                What is the pH of a solution made by adding 6.0 g of sodium hydroxide to 1 dm3 of water at 298K? (Mr NaOH = 40.00)

                (Kw = 1.00 x 10-14 mol2 dm-6 at 298 K)

                • 14.82

                • 12.18

                • 11.18

                • 13.18

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                191 mark

                Which values are correct for a solution that contains 0.056 g of KOH (Mr= 56) in 100 cm3 of water?

                (Kw = 1.00 × 10-14 mol2 dm-6 at 298 K)

                • [H+] = 1.0 × 10-2 mol dm-3 and pH = 2.00

                • [OH-] = 1.0 × 10-2 mol dm-3 and pH = 2.00

                • [H+] = 1.0 × 10-12 mol dm-3 and pH = 12.00

                • [OH-] = 1.0 × 10-12 mol dm-3 and pH = 2.00

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                201 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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                211 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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                22
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                1 mark

                Using appropriate molar ratios which mixtures could act as buffers?

                I. NaOH and CH3COOH

                II. CH3NH2 and CH3NH3Cl

                III. NH3 and HCl

                • I and II only

                • I and III only

                • II and III only

                • I, II and III

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                23
                Sme Calculator
                1 mark

                Which of the following salts would produce a solution with the highest pH if dissolved in water?

                • RbCl

                • CuSO4

                • KCl

                • Na2CO3

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                24
                Sme Calculator
                1 mark

                The acid–base indicator bromophenol blue changes colour from yellow to blue over a pH range of 3.0–4.6. Which statement is correct?

                I. The pKa is between 3.0 and 4.6

                II. In a neutral solution [HIn] > [In-]

                III. It is a suitable indicator for a strong acid, weak base titration

                • I and II only

                • I and III only

                • II and III only

                • I, II and III

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                25
                Sme Calculator
                1 mark

                A titration was carried out using 25.00 cm3 of 0.100 mol dm-3 propanoic acid with 0.100 mol dm-3 sodium hydroxide. The indicator phenolphthalein was used to determine the equivalence point. Phenolphthalein has a pH range of 8.3 to 10.0.  

                If hydrochloric acid was used instead of propanoic acid of the same concentration, which of the following would remain the same? 

                • The volume of base needed to reach the equivalence point

                • The pH at the equivalence point 

                • The y intercept on the pH curve

                • The colour of the solution just before equivalence had been reached 

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                26
                Sme Calculator
                1 mark

                The table below shows data for the and values for some acids and bases at 298 K.

                Acid Ka Base pKb
                C5H6OH 1.02 x 10-10 (C2H5)3N 3.25
                O2NC6H4OH 7.08 x 10-8 C6H5NH2 9.13

                Which two formulas represent the weakest acid and the weakest base in the table?

                • C5H6OH and C6H5NH2

                • O2NC6H4OH and C6H5NH2

                • O2NC6H4OH and (C2H5)3N

                • C5H6OH and (C2H5)3N

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                27
                Sme Calculator
                1 mark

                The ionisation constant of water, Kw , at 40 °C is 2.92 x 10-14. Which of the following statements is correct?

                • pH = 7.0

                • The ionisation of water is exothermic

                • The pH of water is lower at 40 °C than at 25 °C

                • [H+] > [OH-] at 40 °C

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                28
                Sme Calculator
                1 mark

                The Kb value for a base is 8.0 x 10-4 at 298 K. What is the pKa value for the conjugate acid at this temperature? 

                • 10

                • 1.3 x 10-11

                • 3.1

                • 10.9

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                29
                Sme Calculator
                1 mark

                The pKb value of HPO42- is 6.8. What is its conjugate acid and what is the Ka value?

                  Conjugate acid Ka
                A. H2PO4- 7.2
                B. H3PO4 7.2
                C. H3PO4 1.67 x 10-7
                D. H2PO4- 6.3 x 10-8

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                  30
                  Sme Calculator
                  1 mark

                  The strengths of four bases are:

                  • Phenylamine pKb = 9.13
                  • Ethylamine K= 4.46 x 10-4
                  • 3-Nitrophenol pK= 8.36
                  • Ethanol Kb = 3.16 x 10-16

                  What is the order of increasing base strength?

                  • Ethanol < phenylamine < 3-nitrophenol < ethylamine 

                  • Ethanol < 3-nitrophenol < phenylamine < ethylamine 

                  • Ethylamine < 3-nitrophenol < phenylamine < ethanol

                  • Ethylamine < phenylamine < 3-nitrophenol < ethanol

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