1. Consider the reaction HNO2(aq) + H2O(l)
H3O+(aq) + NO2–(aq). Which species is a
conjugate base?
A) HNO2(aq)
B) H2O(l)
C) H3O+(aq)
D) NO2–(aq)
E) two of these
2. In which of the following reactions does the H2PO4– ion act as an acid?
A) H3PO4 + H2O  H3O+ + H2PO4–
B) H2PO4– + H2O  H3O+ + HPO42–
C) H2PO4– + OH–  H3PO4 + O2–
D) The ion cannot act as an acid.
E) Two of these.
3. Using the following Ka values, indicate the correct order of base strength.
HNO2
Ka = 4.0  10–4
HF
Ka = 7.2  10–4
HCN
Ka = 6.2  10–10
4.
5.
6.
7.
A) CN– > NO2– > F– > H2O > Cl–
B) Cl– > H2O > F– > NO2– > CN–
C) CN– > F– > NO2– > Cl– > H2O
D) H2O > CN– > NO2– > F– > Cl–
The pH of a solution at 25°C in which [OH–] = 1.0  10–5 M is:
A) 4.0
B) 5.0
C) 9.0
D) 11.0
Hypobromous acid, HOBr, has an acid dissociation constant of 2.5  10–9 at 25°C. What is the
pOH of a 0.025 M NaOBr solution?
A) 2.0
B) 4.0
C) 8.0
D) 10.0
E) 11.0
A 0.20M solution of a monoprotic weak acid when dissolved in water is 0.5% dissociated.
What is the pH of the solution?
A) 1.0
B) 2.0
C) 3.0
D) Need to know the Ka of the acid.
A 0.33-mol sample of a diprotic acid, H2A, is dissolved in 250 mL of water. The Ka1 of this
acid is 1.0  10–5 and Ka2 is 1.0  10–10. Calculate the concentration of A2– in this solution.
A) 1.0  10–5 M
B) 1.8  10–3 M
C) 3.6  10–3 M
D) 1.0  10–10 M
8. solid sodium carbonate (Na2CO3)
A) acidic
B) basic
C) neutral
D) cannot tell
9. The salt BX, when dissolved in water, produces an acidic solution. Which of the following
could be true?
A) HX is a weak acid.
B) HX is a strong acid.
C) The cation B+ is a weak acid.
D) All of the above could be true.
E) Only A and C could be true.
10. Which of the following species cannot act as a Lewis base?
A) O2–
B) OH–
C) CH4
D) H2S
E) NH3
11. For nitrous acid, HNO2, Ka = 1.0  10–4. Calculate the pH of 0.01 M HNO2.
A) 2.0
B) 3.0
C) 4.0
D) 9.0
12. solid ammonium acetate (NH4C2H3O2). For NH4+, Ka = 5.6  10–10; for C2H3O2–,
Kb = 5.6  10–10.
A) acidic
B) basic
C) neutral
D) cannot tell
13. Which is the strongest acid of the following?
A) HClO2
B) HClO
C) HBrO
D) HIO
14. Which of the following solutions is INCORRECTLY described?
I.
0.2 M NaCN has a pH > 7.
II.
0.2 M FeBr3 is acidic
III.
0.25 M NH4Cl is acidic
A) II only
B) II and III only
C) I and II only
D) All are correctly described
15. Calculate the [H+] in a solution that is 0.10 M in NaF and 0.20 M in HF. (Ka = 7  10–4)
A) 2  10–4 M
B) 2.0 M
C) 1.4  10–3 M
D) 0.070 M
16. 25.0 mL of 0.40 M NaOH is added to a 75.-mL sample of 0.457 M NH3 (Kb for
NH3 = 1.8  10–5). What is the pH of the solution?
A) 1.0
B) 7.5
C) 12
D) 13
17. Which of the following will not produce a buffered solution?
A) 100 mL of 0.1 M Na2CO3 and 50 mL of 0.1 M HCl
B) 100 mL of 0.1 M NaHCO3 and 25 mL of 0.2 M HCl
C) 100 mL of 0.1 M Na2CO3 and 75 mL of 0.2 M HCl
D) 100 mL of 0.1 M Na2CO3 and 50 mL of 0.1 M NaOH
18. Suppose a buffer solution is made from formic and (HCHO2) and sodium formate (NaCHO2).
What is the net ionic equation for the reaction that occurs when a small amount of
hydrochloric acid is added to the buffer?
A) H3O+(aq) + OH–(aq)  2H2O(l)
B) H3O+(aq) + CHO2–(aq)  HCHO2(aq) + H2O(l)
C) HCl(aq)+ OH–(aq)  H2O(l) + Cl–(aq)
D) HCl(aq) + CHO2–(aq)  HCHO2(aq) + Cl–(aq)
You have two buffered solutions. Buffered solution 1 consists of 5.0 M HOAc and 5.0 M
NaOAc; buffered solution 2 is made of 0.050 M HOAc and 0.050 M NaOAc.
19. How do the pHs of the buffered solutions compare?
A) The pH of buffered solution 1 is greater than that of buffered solution 2.
B) The pH of buffered solution 2 is greater than that of buffered solution 1.
C) The pH of buffered solution 1 is equal to that of buffered solution 2.
D) Cannot be determined without the Ka values.
20. How many moles of HCl need to be added to 100 mL of 0.50 M NaZ to have a solution with a
pH of 5.00? (Ka of HZ is 1.0  10–5)? Assume negligible volume of the HCl.
A) 5.0  10–3
B) 5.0  10–2
C) 5.0  10–1
D) 1.0  10–3
21. If 50 mL of 0.10 M HCl are added to 100. mL of 0.01 M NaOH, what is the final pH?
A) 13.12
B) 0.88
C) 13.45
D) 0.55
E) 7.00
22. Consider the titration of 100.0 mL of 0.250 M aniline (Kb = 3.8  10–10) with 0.500 M HCl.
For calculating the volume of HCl required to reach a pH of 8.0, which of the following
expressions is correct? (x = volume in mL of HCl required to reach a pH of 8.0)
A)
= [aniline]
B) [H+] = x
C)
= [aniline]
D)
= [aniline]
23. You dissolve 0.50 grams of an unknown diprotic acid in 200.0 mL of H2O. This solution is
just neutralized by 5.0 mL of a 1.00 M NaOH solution. What is the molar mass of the
unknown acid?
A) 200
B) 100
C) 20
D) 50