Acid Base Equilibria and Solubility Equ

Topics: PH, Buffer solution, Sodium hydroxide Pages: 27 (4694 words) Published: January 7, 2015
August 28, 2009 [PROBLEM SET FROM R. CHANG TEST BANK]

Chapter 16 Acid-Base Equilibria and Solubility Equilibria
Student: ___________________________________________________________________________ NOTE: A table of ionization constants and Ka's is required to work some of the problems in this chapter. 1.

In which one of the following solutions will acetic acid have the greatest percent ionization? A.
B.
C.
D.

2.

Which one of the following is a buffer solution?
A.
B.
C.
D.
E.

3.

0.40 M HCN and 0.10 KCN
0.20 M CH3COOH
1.0 M HNO3 and 1.0 M NaNO3
0.10 M KCN
0.50 M HCl and 0.10 NaCl

Which one of the following combinations cannot function as a buffer solution? A.
B.
C.
D.
E.

4.

0.1 M CH3COOH
0.1 M CH3COOH dissolved in 1.0 M HCl
0.1 M CH3COOH plus 0.1 M CH3COONa
0.1 M CH3COOH plus 0.2 M CH3COONa

HCN and KCN
NH3 and (NH4)2SO4
HNO3 and NaNO3
HF and NaF
HNO2 and NaNO2

Which of the following is the most acidic solution?
A.
B.
C.
D.
E.

0.10 M CH3COOH and 0.10 M CH3COONa
0.10 M CH3COOH
0.10 M HNO2
0.10 M HNO2 and 0.10 M NaNO2
0.10 M CH3COONa

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August 28, 2009 [PROBLEM SET FROM R. CHANG TEST BANK]
5.

Calculate the pH of a buffer solution that contains 0.25 M benzoic acid (C6H5CO2H) and 0.15 M sodium benzoate (C6H5COONa). [Ka = 6.5 × 10-5 for benzoic acid]
A.
B.
C.
D.
E.

6.

A solution is prepared by mixing 500. mL of 0.10 M NaOCl and 500. mL of 0.20 M HOCl. What is the pH of this solution? [Ka(HOCl) = 3.2 × 10-8]
A.
B.
C.
D.
E.

7.

0.97
3.10
4.40
3.70
4.30

Calculate the pH of a solution that is 0.410 M in HOCl and 0.050 M in NaOCl. [Ka(HOCl) = 3.2 × 10-8] A.
B.
C.
D.
E.

9.

4.10
7.00
7.19
7.49
7.80

Calculate the pH of a buffer solution prepared by dissolving 0.20 mole of cyanic acid (HCNO) and 0.80 mole of sodium cyanate (NaCNO) in enough water to make 1.0 liter of solution. [Ka(HCNO) = 2.0 × 10-4] A.

B.
C.
D.
E.

8.

3.97
4.83
4.19
3.40
4.41

0.39
3.94
6.58
7.49
8.40

Calculate the pH of a buffer solution prepared by dissolving 0.20 mole of sodium cyanate (NaCNO) and 1.0 mole of cyanic acid (HCNO) in enough water to make 1.0 liter of solution. [Ka(HCNO) = 2.0 × 10-4] A.

B.
C.
D.
E.

0
3.0
3.7
4.4
5.0

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August 28, 2009 [PROBLEM SET FROM R. CHANG TEST BANK]
10. You are asked to go into the lab and prepare an acetic acid - sodium acetate buffer solution with a pH of 4.00 ± 0.02. What molar ratio of CH3COOH to CH3COONa should be used? A.
B.
C.
D.
E.

0.18
0.84
1.19
5.50
0.10

11. What is the net ionic equation for the reaction that occurs when small amounts of hydrochloric acid are added to a HOCl/NaOCl buffer solution?
A.
B.
C.
D.
E.

H+ + H2O → H3O+
H+ + OCl- → HOCl
HOCl → H+ + OClH+ + HOCl → H2OCl+
HCl + HOCl → H2O + Cl2

12. Consider a buffer solution prepared from HOCl and NaOCl. Which is the net ionic equation for the reaction that occurs when NaOH is added to this buffer?
A.
B.
C.
D.
E.

OH- + HOCl → H2O + OClOH- + OCl- → HOCl + O2Na+ + HOCl → NaCl + OHH+ + HOCl → H2 + OClNaOH + HOCl → H2O + NaCl

13. Over what range of pH is a HOCl - NaOCl buffer effective? A.
B.
C.
D.
E.

pH 2.0 - pH 4.0
pH 7.5 - pH 9.5
pH 6.5 - pH 8.5
pH 6.5 - pH 9.5
pH 1.0 - pH 14.0

14. Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is suitable for making a buffer solution with an optimum pH of 9.2-9.3?
A.
B.
C.
D.
E.

CH3COONa/CH3COOH (Ka = 1.8 × 10-5)
NH3/NH4Cl (Ka = 5.6 × 10-10)
NaOCl/HOCl (Ka = 3.2 × 10-8)
NaNO2/HNO2 (Ka = 4.5 × 10-4)
NaCl/HCl

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August 28, 2009 [PROBLEM SET FROM R. CHANG TEST BANK]
15. Assuming equal concentrations of conjugate base and acid, which one of the following mixtures is suitable for making a buffer solution with an optimum pH of 4.6-4.8?
A.
B.
C.
D.
E.

CH3COO2Na/CH3COOH (Ka = 1.8 × 10-5)...
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