CHEM 1412 Practice exam 2
Chapter 14-16
1. Give the equilibrium as PO43- (aq) + H2O(l)  HPO42- (aq) + OH- (aq)
A)
PO42– is an acid
B)
HPO42– is a conjugate base
C)
HPO42– is a conjugate acid
D)
H2O is a conjugate base
2. Which of the following statements is true with respect to the reaction below?
A)
B)
C)
D)
The reaction favors the formation of CH3COO–.
CH3COO– is a weaker base than Cl–.
Cl– is a weaker base than CH3COO–
The reaction favours the formation of HCl.
3. Which of the following indicates the most basic solution?
A) [H+] = 1  10–9 M
B) pOH = 5.7
C) [OH–] = 7  10–5 M
D) pH = 3.2
4. The pH of 4 x 10–3 M Ba(OH)2 will be _____?
5. Acetic acid, (HC2H3O2) is a weak acid (Ka = 1.8  10–5). Calculate the pH of a 4.6 M HC2H3O2
solution.
6. The pH of a 0.1 M aqueous NH3 solution (Kb = 1.8x 10–5) will be
A) 2.89
B) 10.11
C) 11.11
D) 3.89
+
Hint: the reaction is NH3 +H2O  NH4 + OH
7. A solution of acetic acid has a pH of 3.45. What is the concentration of acetic acid in this
solution? Ka for CH3COOH is 1.8×10-5.
(A) 3.55×10-8
(B) 1.80×10-5
(C) 7.00×10-3
(D) 3.45
(E) 7.00
8. The Kb for dimethylamine, CH3NH2, at 25oC is 4.0×10-4. What’s the Ka of its conjugate acid?
(A) 9.6×10-3
(B) 9.6×10-4
(C) 1.0×10-14
(D) 1.04×10-11
(E) 2.5×10-11
9. Which is the strongest acid of the following?
A) HClO3
B) HClO2
C) HBrO
D) HIO
10. Predict the pH(>7,<7,=7) of the following solution:
NaBr, K2SO3, NH4NO2, Cr(NO3)3
11. Which of the following is a Lewis acid?
(A) NH3
(B) CO32(C) Al3+
(D) BF4-
(E) CN-
12. Which of the following pairs can make a buffer solution?
(A) KCl and HCl
(B) KHSO4 and H2SO4
(C) CH3COONa and CH3COOH
(D) HNO3 and NaNO3
13.The pH of a solution containing 0.20 M NH3 and 0.30 M NH4Cl is _____.
A) 8.09
B) 11.12
C) 9.07
D) 10.05
14. The pH of 1.00L of the buffer containing 1.00 M CH3COONa and 1.00 M CH3COOH after
the addition of 0.080 mole NaOH is _____.
A)
3.82
B)
6.12
C)
4.81
D)
5.28
15. Methyl orange is an indicator with a Ka of 1  10–4. Its acid form, HIn, is red, while its base
form, In–, is yellow. At pH 6.0, the indicator will be
A) red
B) orange
C) yellow
D) blue
E) not enough information
16. In titrating 0.40 M hydrochloric acid, HCl, with 0.40 M NaOH at 25°C, the solution at the
equivalence point is
A) 0.40 M NaCl
B) very acidic
C) slightly acidic
D) 0.20 M HCl and 0.40 M NaOH
E) 0.20 M NaCl
17. In a titration experiment 20mL of 0.500 M H2SO4 neutralized 40.0 mL of NaOH. The
concentration of the NaOH solution is ____.
A) 0.500 M
B) 0.250 M
C) 0.125 M
D) 0.0250 M
18. Exactly 100 mL of 0.10M HNO2 are titrated with a 0.10M NaOH solution. What is the pH
at the equivalence point?
A) 8.47
B) 7.39
C) 8.02
D) 6.54
E) 8.17
19. The correct mathematical expression for finding the molar solubility (s) of Sn(OH)2 is:
A) 2s2 = Ksp
B) 2s3 = Ksp
C) 108s5 = Ksp
D) 4s3 = Ksp
E) 8s3 = Ksp
20. The molar solubility of silver phosphate, Ag3PO4, is 1.6 x 10–5 mol/L. Its solubility product
Ksp is _____.
A) 1.8 x 10–10
B) 1.8 x 10–18
C) 2.96x10–12
D) 5.76 x10–14
E) 3.57 x10–16
21. The molar solubility for CaF2 in water at 25oC is 2.1×10-4 M. What is its Ksp?
A) 6.8x10-10
B) 3.7x10-11
C) 3.7x10-8
D) 8.6x10-14
E) 8.6x10-10
22.The molar solubility of BaSO4 (Ksp=1.1x10-10) in a solution containing 2.0 M SO42– ions is
A) 7.3 x10–9 M
B) 5.5 x10–11 M
C) 1.1 x10–10 M
D) 8.1 x10–7 M
E) 8.1 x10–9 M
23. The molar solubility of Fe(OH)2(Ksp= 1.6x10-14) at pH 8.00 is _____.
A) 0.016 M
B) 1.6 M
C) 0.16 M
D) 1.6 x 10–3 M
E) 1.6 x 10–4 M
24. If 2.50 g of CuSO4 is dissolved in 9.0x102 mL of 0.30 M NH3, the concentration of [Cu2+] at
equilibrium in the solution is _____. (Kf = 5.0x1013)
A) 0.115 M
B) 0.0174 M
C) 0.0016 M
D) 1.8 x10–10 M
E) 1.2 x10–13 M
25. Consider the following three complex ions of Ag+ and their formation constants, Kf.
Ag(NH3)2+
Ag(CN)2–
AgBr2–
Kf = 1.7  107
Kf = 5.6  1018
Kf = 1.0  1011
Which of the following responses is true?
A) Ag (NH3)2+ is more stable than Ag (CN)2–.
B) Adding a strong acid (HNO3) to a solution that is 0.010 M in AgBr2– would tend to dissociate
the complex ion.
C) Adding a strong acid (HNO3) to a solution that is 0.010 M in Ag(NH3)2+ would tend to
dissociate the complex ion.
D) A & B
E) None of them