IBDP Official Exam Material
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Topic 8: Acids and Bases
For both SL and HL students
1. [1 mark]
Equal volumes of 0.10 mol dm−3 weak acid and strong acid are titrated with 0.10 mol dm−3 NaOH solution. Which of these is the same for the two acids?
A. Initial pH
B. Heat evolved in the neutralization
C. Volume of NaOH for complete neutralization
D. Initial electrical conductivity
2. [1 mark]
Which species has the weakest conjugate base?
A. HCl
B. NH4+
C. HCO3−
D. H2O
3. [1 mark]
Which 0.01 mol dm–3 aqueous solution has the highest pH?
A. HCl
B. H2SO4
C. NaOH
D. NH3
4. [1 mark]
Which of the 0.001 mol dm−3 solutions is most likely to have a pH of 11.3?
A. Ca(OH)2 (aq)
B. H3PO4 (aq)
C. NaOH (aq)
D. NH4OH (aq)
5. [1 mark]
What is the strongest acid in the equation below?
H3AsO4 + H2O ⇌ H2AsO4− + H3O+ Kc = 4.5 × 10−4
A. H3AsO4
B. H2O
C. H2AsO4−
D. H3O+
6. [1 mark]
Write an equation that shows how sulfur dioxide can produce acid rain.
7. [2 marks]
State the meaning of a strong Brønsted–Lowry acid.
8. [1 mark]
Which ions are present in an aqueous solution of Na2CO3?
I. HCO3−
II. OH−
III. CO32−
II. OH−
III. CO32−
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
9. [1 mark]
What is the conjugate acid of HS−?
A. H2S
B. S2−
C. H2SO3
D. H2SO4
10. [1 mark]
Which solution has a pH of 9?
A. 1.0 × 10−9 mol dm−3 HCl (aq)
B. 1.0 × 10−5 mol dm−3 KOH (aq)
C. 1.0 × 10−9 mol dm−3 KOH (aq)
D. 1.0 × 10−5 mol dm−3 HCl (aq)
11. [1 mark]
Which cannot act as a Brønsted–Lowry base?
A. HPO42−
B. H2O
C. CH4
D. NH3
12. [1 mark]
Which causes acid deposition?
A. SO2
B. SiO2
C. SrO
D. CO2
13. [1 mark]
Phosphoric acid, H3PO4, can undergo stepwise neutralization, forming amphiprotic species.
Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.
14. [2 marks]
Formulate two equations to show the amphiprotic nature of H2PO4−.
15. [2 marks]
Calculate the concentration of H3PO4 if 25.00 cm3 is completely neutralised by the addition of 28.40 cm3 of 0.5000 mol dm−3 NaOH.
16. [1 mark]
Outline the reason that sodium hydroxide is considered a Brønsted–Lowry base.
17. [2 marks]
Justify why sulfur is classified as a non-metal by giving two of its chemical properties.
18. [1 mark]
Suggest why this process might raise environmental concerns.
19. [1 mark]
In aqueous solution, hydrogen sulfide acts as an acid.
State the formula of its conjugate base.
20. [1 mark]
Saturated aqueous hydrogen sulfide has a concentration of 0.10 mol dm−3 and a pH of 4.0. Demonstrate whether it is a strong or weak acid.
21. [1 mark]
Calculate the hydroxide ion concentration in saturated aqueous hydrogen sulfide.
22. [2 marks]
Determine the volume, in dm3, of 0.015 mol dm−3 calcium hydroxide solution needed to neutralize 35.0 cm3 of 0.025 mol dm−3 HCl (aq).
23. [2 marks]
Saturated calcium hydroxide solution is used to test for carbon dioxide. Calculate the pH of a 2.33 × 10−2 mol dm−3 solution of calcium hydroxide, a strong base.
24. [1 mark]
Outline how one calcium compound in the lime cycle can reduce a problem caused by acid deposition.
25. [1 mark]
Which substance will not produce copper(II) chloride when added to dilute hydrochloric acid?
A. Cu s
B. CuOH)2 s
C. CuCO3 s
D. CuO s
26. [1 mark]
Which of these acids has the weakest conjugate base?
A. HCl
B. CH3COOH
C. NH4Cl
D. C6H5COOH
27. [1 mark]
What is the difference between a conjugate Brønsted–Lowry acid–base pair?
A. Electron pair
B. Positive charge
C. Proton
D. Hydrogen atom
28. [1 mark]
Which is an example of an amphiprotic species?
A. Al2O3
B. CO32−
C. P4O10
D. HPO42−
29. [1 mark]
Which solution is basic at 25 °C?
Kw = 1.0 × 10−14
A. [H+] = 1.0 × 10−3 mol dm−3
B. [OH−] = 1.0 × 10−13 mol dm−3
C. solution of pH = 4.00
D. [H3O+] = 1.0 × 10−13 mol dm−3
30. [1 mark]
Which is not a source of oxides of sulfur and nitrogen?
A. burning coal
B. internal combustion engines
C. burning methane
D. volcanic eruptions
31. [1 mark]
What is the pH of 0.001 mol dm−3 NaOH (aq)?
A. 1
B. 3
C. 11
D. 13
32. [1 mark]
What is the major reason why the pH of unpolluted rain is less than 7?
A. methane
B. carbon dioxide
C. nitrogen oxides
D. sulfur dioxide
If you need the markscheme, including the examiners' reports for each question, and more exam and teaching materials on this topic, contact me through the contact page