AQA A Level Chemistry

Topic Questions

A LevelChemistryAQATopic Questions5. Advanced Physical Chemistry (A Level only)5.5 Fundamentals of Acids & Bases (A Level only)

5.5 Fundamentals of Acids & Bases (A Level only)

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11 mark

The pH of hydrochloric acid, HCl (aq), with a concentration of 0.50 mol dm-3 is

  • 0.50

  • 0.30 

  • -0.30

  • 1.00

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21 mark

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

  • Kw = begin mathsize 14px style fraction numerator left square bracket straight H to the power of plus right square bracket left square bracket OH to the power of minus right square bracket over denominator left square bracket straight H subscript 2 straight 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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31 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 pairing

  • SO4- is acting as Brønsted–Lowry acid

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

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

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41 mark

What is the pH of a 0.005 mol dm-3 solution of potassium hydroxide, KOH, at 25 ℃?

(Kw = 1.00 x 10-14 mol2 dm-6 at 25 ℃)

  • 2.30

  • 11.70

  • 12.70

  • 10.70

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51 mark

Which of the following is the concentration of a strong acid with a pH of 1.52?

  • 0.06 mol dm-3

  • 0.03 mol dm-3

  • 0.18 mol dm-3

  • 0.15 mol dm-3

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11 mark

Pure water is heated from freezing point to boiling point at atmospheric pressure.

The initial pH is 7.47 and drops by a pH of 1.33 to become increasingly acidic as it boils.

What are the values of Kw at 0 oC and at 100 oC?

 

Kw  x 10-14 (mol2 dm-6) at 0 oC

Kw x 10-14 (mol2 dm-6) at 100 oC

A

0.115

52.5

B

1.15

5.25

C

0.114

52.4

D

3.39

7.24

 

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21 mark

Which of the solutions below contain the same amount of H+(aq) in moles? (assume complete dissociation in H2SO4)

 

Acid

pH of stock

Volume and dilution

1

HCl

2.00

250 cm3 made from 25 cm3 HCl  topped up with distilled water

2

CH3COOH

3.00

250 cm3 taken straight from a stock bottle

3

HNO3

3.00

 250 cm3 made from 125 cm3 HNO3 topped up with distilled water

4

H2SO4

1.50

250 cm3 made from 125 cm3 H2SO4 topped up with distilled water

 

 

Solution 1

Solution 2

Solution 3

Solution 4

A

✓

✓

✓

✓

B

✓

✓

X

X

C

✓

✓

X

✓

D

X

X

X

X

 

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31 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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41 mark

This question is about the reaction naphthalene-1,5-disulfonic acid, known as ‘Armstrong’s acid’, C10H6(SO3H)2. This strong organic acid can react to produce a diol, as seen below.

5-5-aqa-a-level-chemistry-mcq-q4-hard

The NaOH is added to a 250 cm3 solution containing the acid with an initial pH of 1.50. Assume complete dissociation.

The mass of naphthalene-1,5-disulfonic acid used in this reaction is

  • 0.819 g

  • 1.14 g

  • 2.28 g

  • 4.56 g

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51 mark

Barium hydroxide is soluble in water, forming solutions of up to pH 13.

(Kw = 1.00 x 10-14 mol2 dm-6 at 25 ℃)

What is the number of moles of barium hydroxide in a 100 cm3 solution with a pH of 11.3 at 25 ℃?

  • 3.99 x 10-4

  • 9.98 x 10-4 

  • 1.00 x 10-4 

  • 9.98 x 10-5

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11 mark

The pH of water at 50 ℃ is

(Kw = 5.48 x 10-14 mol2 dm-6 at 50 ℃)

  • 13.26

  • 7.00

  • 2.34

  • 6.63

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21 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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31 mark

The pH of 0.50 mol dm-3 KOH at 25 ℃ is

(Kw = 1.00 x 10-14 mol2 dm-6 at 25 ℃)

  • 14.30

  • 0.30

  • 13.70

  • 13.7

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41 mark

Which of the following is correct for the equation:

NH4+ + OH- ⇌ H2O + NH3

  • NH4+ is the base

  • H2O is the conjugate acid

  • NH3 is the conjugate acid

  • OH- is the acid 

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51 mark

Which of the following is the pH of 0.08 mol dm-3 Ba(OH)2?

(Kw = 1.00 x 10-14 mol2 dm-6 at 25 ℃)

  • 14.80

  • 13

  • 13.20

  • 12.90

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