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REVIEW 5 Acid/Base Review – Everything is (aq) unless specified otherwise!
1. Which of the following is NOT an acid-base conjugate pair?
A. HCN and CN─ C. H2S and OH─
B. H2O and OH─ D. NH4+ and NH3
2. Knowing that HF is a stronger acid than HC2H3O2, determine, if possible, in which direction the following equilibrium lies:
HF + C2H3O2─ ⇄ F─ + HC2H3O2
A. Left
B. Right
C. Perfectly balanced
D. Cannot be determined
3. At 50oC the water ionization constant, Kw is 5.48 x 10-14. What is [H3O+] in neutral water at 50oC?
A. 1.00 x 10-7 M C. 5.48 x 10-7 M
B. 2.34 x 10-7 M D. 2.74 x 10-7 M
4. We have a 0.00100 M solution of Sr(OH)2 solution at 25oC. What is [H3O+] in this solution?
A. 1.00 x 10-3 M C. 2.00 x 10-3 M
B. 1.00 x 10-11 M D. 5.00 x 10-12 M
5. We have a 5.43 x 10-4 solution of HNO3 at 25oC. What is [OH─] in this solution?
A. 1.84 x 10-11 M C. 5.43 x 10-4 M
B. 5.43 x 10-10 M D. 3.76 x 10-8 M
6. We have 500. mL of a solution that contains 0.0854 g of NaOH. What is the pH of this solution at 25oC?
A. 2.36 C. 2.67
B. 11.63 D. 11.33
For each solution below, tell if the pH is < 7, pH = 7 or if pH > 7.
7. 0.10 M HNO3
8. 0.012 M KOH
9. 0.15 M acetic acid
10. 0.56 M Na2CO3
11. 0.45 M KBr
12. 0.15 M (NH4)2S
13. Predict the products of the following acid-base reaction: NH3+ HNO3à
A. NH2OH + HNO2
B. NH4NO3 + H2O
C. NH4OH
D. No reaction
The following reactants are mixed in equimolar portions. Predict the resulting solution will be (A) acidic, (B) Basic, (C) neutral (D) cannot be determined.
14. HCl + NaHCO3 à ?
15. HCl + NaOH à ?
16. HF + KOH à ?
17. H2SO4 + KOH à ?
18. CH3COOH + NH3 à ?
Indicate whether the following describes and acid, base, or both
19. Donates H+
20. Solution conducts electricity
21. Turns litmus paper red
22. Pink with phenolphthalein
23. Reacts with active metals
24. Tastes bitter
25. Feels slippery
26. Which of the following substances is amphoteric?
A. Al(OH)3 D. Ca(OH)2
B. HCN E. HI
C. CsBr
27. Which of the following substances is amphoteric? (Select all correct answers)
A. SO42─ C. H2PO42─
B. H2O D. H2SO4
28. In which of the following is the acid strength ranking INCORRECT?
A. H2SO4 > H2SO3
B. HNO3 > HNO2
C. HClO4 > HClO3
D. HClO3 > HBrO3
E. H2SeO3 > H2SO3
29. Rank the hydrohalic acids from strongest to weakest:
A. HF > HCl > HBr > HI
B. HI > HBr > HCl > HF
C. HCl > HBr > HI > HF
D. HF > HI > HBr > HCl
30. Rank the chlorine based acids from strongest to weakest.
A. HClO > HClO2 > HClO3 > HClO4
B. HClO4 > HClO3 > HClO2 > HClO
31. Which statement concerning the autoionization (self-ionization) of water is FALSE?
2 H2O(l) ⇄ H3O+ + OH-(aq)
A. This reaction is an acid-base reaction according to the Bronsted-Lowry theory.
B. Water is amphiprotic.
C. A H2O molecule may react as an acid by donating a proton.
D. In this reaction H3O+ and OH- are a conjugate acid- base pair.
E. A H2O molecule may react as a base by accepting a proton.
32. Based on the reactions we have studied, ammonia can be considered as:
A. an Arrhenius base (only).
B. a Lewis base (only).
C. a Bronsted-Lowry base (only).
D. both an Arrhenius base and a Lewis base.
E. both a Bronsted-Lowry base and a Lewis base.
33. Which one of the following is NOT a strong, soluble base?
A. Ba(OH)2 D. Ca(OH)2
B. Cu(OH)2 E. KOH
C. RbOH
34. The conjugate base of ammonia is:
A. NH3 D. NH4+
B. NH2- E. OH-
C. none of these
35. According to the Lewis theory, a base:
A. is a proton acceptor.
B. is a proton donor.
C. makes available a share in a pair of electrons.
D. is any compound that contains electron pairs.
E. accepts a share in a pair of electrons.
36. Which of the following is the strongest acid?
A. HClO3 C. HClO2
B. HBrO2 D. HBrO3
37. Which of the following is the strongest acid?
A. H3AsO4 C. H3AsO3
B. H3PO4 D. H3PO3
38. Water cannot function as which one of the following?
A. A Bronsted acid C. Bronsted base
B. A Lewis acid D. a Lewis base
39. We have a solution of NH3. What effect will the addition of HCl have on the pH of the solution?
A. Increase pH C. no effect
B. Decrease pH
EQUILIBRIA, BUFFERS, TITRATIONS (you must look up Ka values)
40. What is the pH of a 0.155 M solution of H2S at 250C?
A. 13.39 C. 3.50
B. 3.90 D. 2.88
41. What is the [OH─] in a 0.10 M solution of NaCN at 25oC?
A. 5.00 x 10-3 M C. 1.57 x 10-3 M
B. 6.37 x 10-12 M D. 4.67 x 10-5 M
42. What is the pH of a 0.144 M solution of NaF at 25oC?
A. 8.15 C. 9.12
B. 5.84 D. 7.00
43. If the pH of a 0.015 M solution of hypochlorous acid is 4.64, what is the concentration of the hypochlorite ion, OCl─, in solution?
A. 4.37 x 10-4 M C. 4.37 x 104 M
B. 2.29 x 10-5 M D. 4.38 x 10-10 M
44. What is the value of Ka for hypochlorous acid from the previous question?
A. 2.30 x 10-5 C. 1.53 X 10-3
B. 5.25 x 10-10 D. 3.50 x 10-8
45. We mix 50.0 mL of 0.050 M HNO3 and 25.0 mL of 0.10 M NaCH3COO. What is the pH of the resulting solution?
A. 3.11 C. 2.87
B. 3.02 D. 10.89
46. We add 1.00 mL of 10.0 M NaOH to 50.0 mL of 0.20 M HNO2. What is the pH of the resulting solution?
A. 8.32 C. 9.17
B. 5.68 D. 10.3
47. We have 100. mL of a 0.10 M solution of CH3COOH. How many grams of NaCH3COO must be added to make a buffer solution of pH 5.00? Ka acetic acid = 1.8 x 10-5
A. 0.88 g C. 0.56 g
B. 24.7 g D. 1.48 g
48. A 0.10 M solution of HF is 8.1% ionized. What is the Ka?
A. 7.6 x 10-4 D. 8.8 x 10-4
B. 8.4 x 10-4 E. 6.4 x 10-4
C. 7.1 x 10-4
49. A 1.50 g sample of vitamin C is dissolved in 100.0 mL of water and titrated with 0.250 M NaOH to the methyl orange end point. The volume of the base used is 34.1 mL. What is the molar mass of Vitamin C assuming one dissociable proton per molecule?
A. 176 g/mol D. 139 g/mol
B. 164 g/mol E. 152 g/mol
C. 146 g/mol
50. A 25.00 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution at the points where 25.1 and 25.5 mL of NaOH have been added?
A. 10.50, 11.20 D. 10.00, 11.00
B. 10.00, 10.70 E. 10.30, 11.20
C. 10.30, 11.00
51. A 25.00 mL sample of 0.100 M CH3CO2H is titrated with 0.100 M NaOH. What is the pH of the solution at the points where 24.5 and 25.5 mL of NaOH have been added? (Ka = 1.8 x 10-5)
A. 7.00, 8.00 C. 6.13, 9.85
B. 6.44, 9.85 D. 6.43, 11.00
52. During what type of titration might the jump around the end point be from about pH 10 to pH about 4?
A. Strong acid with strong base
B. Strong acid with weak base
C. Weak acid with strong base
D. Weak acid with weak base
E. Strong base with strong acid
F. Weak base with strong acid
G. Strong base with weak acid
H. Weak base with weak acid
53. During what type of titration might the jump around the end point be from about pH 4 to pH about 12?
A. Strong acid with strong base
B. Strong acid with weak base
C. Weak acid with strong base
D. Weak acid with weak base
E. Strong base with strong acid
F. Weak base with strong acid
G. Strong base with weak acid
H. Weak base with weak acid
54. Which of the following mixtures will be a buffer when dissolved in a liter of water?
A. 1. 0.2 mol Ba(OH)2 and 0.3 mol HClO2
B. 2. 0.2 mol KNO3 and 0.2 mol HClO3
C. 3. 0.4 mol NH4Cl and 0.4 mol NaOH
D. 4. 0.2 mol HClO3 and 0.1 mol LiOH
E. 5. 0.4 mol HCOOH and 0.2 mol NaOH
AP Chem. Leggett 2013