IBChemistry: HLDPExam Questions8. Acids & Bases8.2 More About Acids

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First teaching 2014

Last exams 2024

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More About Acids (DP IB Chemistry: HL)

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8.2 More About Acids

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8.2 More About Acids

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11 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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21 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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31 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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41 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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51 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?

  • fraction numerator 34.3 blank cross times blank 0.125 over denominator 26.0 end fraction

  • fraction numerator 2 blank cross times blank 34.3 blank cross times blank 0.125 over denominator 26.0 end fraction

  • fraction numerator 34.3 blank cross times blank 0.125 over denominator 2 cross times 26.0 end fraction

  • fraction numerator 26.0 over denominator 2 blank cross times blank 34.3 blank cross times blank 0.125 end fraction

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61 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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71 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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81 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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91 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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101 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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11 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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21 mark

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

  • 1

  • 3

  • 11

  • 13

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31 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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41 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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51 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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61 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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    71 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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    81 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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    91 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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      101 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

      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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      21 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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      31 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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      41 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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      51 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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      61 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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        71 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?

        • fraction numerator blank 0.02 blank cross times blank 23.70 over denominator 2 space cross times space 0.03 end fraction

        • begin mathsize 16px style fraction numerator 0.03 over denominator 2 blank cross times blank 0.02 blank cross times blank 23.70 end fraction end style

        • begin mathsize 16px style fraction numerator 0.02 blank cross times blank 23.70 over denominator 0.03 end fraction end style

        • begin mathsize 16px style fraction numerator 0.03 blank cross times blank 23.70 blank over denominator 2 blank cross times blank 0.02 end fraction end style

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        81 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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        91 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 = 40.0)

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

        • -logbegin mathsize 16px style open parentheses fraction numerator 6.0 blank cross times blank 10 to the power of negative 14 end exponent over denominator 40.0 end fraction close parentheses end style

        • -logbegin mathsize 16px style open parentheses fraction numerator 40.0 blank cross times blank 10 to the power of negative 13 end exponent over denominator 6.0 blank cross times blank 1000 end fraction close parentheses end style

        • -logbegin mathsize 16px style open parentheses fraction numerator 4.0 blank cross times blank 10 to the power of negative 15 end exponent over denominator 6.0 end fraction close parentheses end style

        • -logbegin mathsize 16px style open parentheses fraction numerator 4.0 blank cross times blank 10 to the power of negative 13 end exponent over denominator 6.0 end fraction close parentheses end style

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        101 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 x 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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