A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
96) Which solution has the largest percent dissociation of HA?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems
97) Which of the solutions are buffer solutions?
A) (1) and (2) B) (1) and (3) C) (2) and (3) D) (2) and (4) Answer: B
Topic: Conceptual Problems
98) Which solution has the greatest buffer capacity?
A) (1) B) (2) C) (3) D) (4) Answer: C
Topic: Conceptual Problems
99) For which solution(s) is pH = pKa?
A) only solution (1) B) only solution (2) C) only solution (3) D) solutions (1) and (3) Answer: D
Topic: Conceptual Problems
The following pictures represent solutions that contain a weak acid HA (pKa = 5.0) and its potassium salt KA. Unshaded spheres represent H atoms and shaded spheres represent A- ions. (K+, H3O+, OH-, and solvent H2O molecules have been omitted for clarity.)
100) Which solution has the highest pH?
A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
101) Which solution has the lowest pH?
A) (1) B) (2) C) (3) D) (4) Answer: C
Topic: Conceptual Problems
102) Which solution has the largest percent dissociation of HA?
A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
103) Which of these solutions are buffers?
A) (1) and (2) B) (1) and (3) C) (1), (2) and (3)
D) All are buffer solutions.
Answer: D
Topic: Conceptual Problems
104) Which solution has the greatest buffer capacity?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems
105) For which of these solutions is pH = pKa?
A) All have pH = pKa.
B) (1), (2) and (3) C) (1) and (4) D) (2) and (3) Answer: C
Topic: Conceptual Problems
The following pictures represent solutions that contain a weak acid HA (pKa = 5.0) and its potassium salt KA. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres represent A- ions. (K+, H3O+ initially present, OH- initially present and solvent water molecules have been omitted for clarity.)
106) Which picture represents the equilibrium state of the solution after addition of one H3O+ ion to the solution shown in picture (1)?
A) (2) B) (3) C) (4) D) (5) Answer: C
Topic: Conceptual Problems
107) Which picture represents the equilibrium state of the solution after addition of one OH- ion to the solution shown in picture (1)?
A) (2) B) (3) C) (4) D) (5) Answer: B
Topic: Conceptual Problems
The following pictures represent solutions at various points in the titration of a weak acid HA with aqueous KOH. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres represent A- ions. (K+, H3O+ initially present, OH- initially present and solvent water molecules have been omitted for clarity).
108) Which picture represents the solution before the addition of any KOH?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems
109) Which picture represents the solution before the equivalence point?
A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
110) Which picture represents the solution at the equivalence point?
A) (1) B) (2) C) (3) D) (4) Answer: A
Topic: Conceptual Problems
111) Which picture represents the solution after the equivalence point?
A) (1) B) (2) C) (3) D) (4) Answer: C
Topic: Conceptual Problems
The following pictures represent solutions at various stages in the titration of a weak diprotic acid H2A with aqueous KOH. Unshaded spheres represent H atoms, black spheres represent oxygen atoms, and shaded spheres represent A2- ions. (K+, H3O+ initially present, OH- initially present and solvent water molecules have been omitted for clarity).
112) Which picture represents the system halfway to the first equivalence point?
A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
113) Which picture represents the system at the first equivalence point?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems
114) Which picture represents the system halfway between the first and second equivalence points?
A) (1) B) (2) C) (3) D) (4) Answer: A
Topic: Conceptual Problems
115) Which picture represents the system beyond the second equivalence point?
A) (1) B) (2) C) (3) D) (4) Answer: C
Topic: Conceptual Problems
116) Which picture represents the system with the highest pH?
A) (1) B) (2) C) (3) D) (4) Answer: C
Topic: Conceptual Problems
117) Which picture represents the system with the lowest pH?
A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
Use the graphs below to answer the following questions.
118) What is the characteristic pH-titrant curve for the titration of a strong acid by a strong base?
A) A B) B C) C D) D Answer: B
Topic: Conceptual Problems
119) What is the characteristic pH-titrant curve for the titration of a strong base by a strong acid?
A) A B) B C) C D) D Answer: C
Topic: Conceptual Problems
120) What is the characteristic pH-titration curve for the titration of a weak acid by a strong base?
A) A B) B C) C D) D Answer: A
The following plot shows two titration curves, each representing the titration of 50.00 mL of 0.100 M acid with 0.100 M NaOH.
121) Which point a-d represents the equivalence point for the titration of a strong acid?
A) point a B) point b C) point c D) point d Answer: D
Topic: Conceptual Problems
122) Which point a-d represents the equivalence point for the titration of a weak acid?
A) point a B) point b C) point c D) point d Answer: C
Topic: Conceptual Problems
123) At which point a-d is the pKa of the acid equal to the pH?
A) point a B) point b C) point c D) point d Answer: A
Topic: Conceptual Problems
124) Which points a-d represent the half-equivalence point and the equivalence point, respectively, for the titration of a weak acid?
A) points a and b B) points a and c C) points b and d
125) Which point a-d represents a buffer region?
A) point a B) point b C) point c D) point d Answer: A
Topic: Conceptual Problems
The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H2A with NaOH.
126) A buffer region is indicated by which point(s) a-d?
A) point a B) points a and c C) point b
D) points b and d Answer: B
Topic: Conceptual Problems
127) Which point a-d represents the HX-/X2- buffer region?
A) point a B) point b C) point c D) point d Answer: C
Topic: Conceptual Problems
128) Which point a-d represents the H2X/HX- buffer region?
A) point a B) point b C) point c D) point d Answer: A
Topic: Conceptual Problems
129) Which point a-d represents the first equivalence point?
A) point a B) point b C) point c D) point d Answer: B
Topic: Conceptual Problems
130) Which point a-d represents the second equivalence point?
A) point a B) point b C) point c D) point d Answer: D
Topic: Conceptual Problems
131) Which point a-d represents pKa1?
A) point a B) point b C) point c D) point d Answer: A
Topic: Conceptual Problems
132) Which point a-d represents pKa2?
A) point a B) point b C) point c D) point d Answer: C
Topic: Conceptual Problems
133) What is the pH at the first equivalence point?
A) pH = pKa1 B) pH = 14 - pKa1 C) pH = (pKa1 + pKa2)/2 D) pH = pKa1 + pKa2
134) The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H2A+
with NaOH. Which point a-d represents the isoelectric point?
A) point a B) point b C) point c D) point d Answer: B
Topic: Conceptual Problems
The following pictures represent solutions of CuS, which may also contain ions other than Cu2+ and S2- which are not shown. Gray spheres represent Cu2+ ions and dotted spheres represent S2- ions.
135) If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are unsaturated?
A) only (2) B) only (3) C) only (4) D) (3) and (4) Answer: D
Topic: Conceptual Problems
136) If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are saturated?
A) (2) B) (3) C) (4)
D) None of these Answer: D
Topic: Conceptual Problems
137) If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are supersaturated?
A) (2) B) (3) C) (4)
D) None of these Answer: A
Topic: Conceptual Problems
The following pictures represent solutions of AgCl, which may also contain ions other than Ag+ and Cl- which are not shown. Gray spheres represent Ag+ ions and dotted spheres represent Cl- ions.
138) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of HCl is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems
139) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of HNO3 is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: A
Topic: Conceptual Problems
140) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of AgNO3 is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
141) If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of NH3 is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems
The following pictures represent solutions of CaCO3, which may also contain ions other than Ca2+ and CO32- which are not shown. Gray spheres represent Ca2+ ions and unshaded spheres represent CO32- ions.
142) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of NaOH is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems
143) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of HNO3 is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: B
144) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of Ca(NO3)2 is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: B
Topic: Conceptual Problems
145) If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of K2CO3 is added and equilibrium is restored?
A) (1) B) (2) C) (3) D) (4) Answer: D
Topic: Conceptual Problems 15.2 Algorithmic Questions
1) What is the hydronium ion concentration in a solution prepared by mixing 50.00 mL of 0.10 M HCN with 50.00 mL of 0.030 M NaCN? Assume that the volumes of the solutions are additive and that Ka = 4.9 × 10-10 for HCN.
A) 1.5 × 10- 10 M B) 4.9 × 10-10 M C) 1.6 × 10- 9 M D) 7.0 × 10-6 M Answer: C
Topic: Section 15.2 The Common-Ion Effect
2) What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of 0.0 10 M CH3CO2Na? Assume that the volume of the solutions are additive and that Ka = 1.8 × 10-5 for CH3CO2H.
A) 2.87 B) 3.74 C) 4.7 5 D) 5. 74 Answer: B
Topic: Section 15.2 The Common-Ion Effect
3) What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M NH3 with 5.00 mL of 0.10 M NH4Cl? Assume that the volume of the solutions are additive and that Kb = 1.8 × 10-5 for NH3.
A) 8. 25 B) 10.26 C) 10.25 D) 11.13 Answer: C
Topic: Section 15.2 The Common-Ion Effect
4) What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M methylamine, CH3NH2, with 20.00 mL of 0.10 M methylammonium chloride, CH3NH3Cl? Assume that the volume of the solutions are additive and that Kb = 3.70 × 10-4 for methylamine.
A) 10.17 B) 10.57 C) 10.97 D) 11.78 Answer: C
Topic: Section 15.2 The Common-Ion Effect
5) What is the pH of a buffer system prepared by dissolving 10.70 grams of NH4Cl and 25.00 mL of 12 M NH3 in enough water to make 1.000 L of solution? Kb = 1.80 × 10-5 for NH3.
A) 9.08 B) 9.26 C) 9. 43 D) 11. 32 Answer: C
Topic: Section 15.3 Buffer Solutions
6) What is the [CH3CO2-]/[CH3CO2H] ratio necessary to make a buffer solution with a pH of 4.34?
Ka = 1.8 × 10-5 for CH3CO2H.
A) 0. 39:1 B) 0. 91:1 C) 1. 09:1 D) 2.5:1 Answer: A
Topic: Section 15.3 Buffer Solutions
7) What volume of 5.00 × 10–3 M HNO3 is needed to titrate 80.00 mL of 5.00 × 10–3 M Ca(OH)2 to the equivalence point?
A) 10.0 mL B) 40.0 mL C) 80.0 mL D) 160. mL Answer: D
Topic: Section 15.6 Strong Acid - Strong Base Titrations
8) What is the pH of a solution made by mixing 25.00 mL of 0. 100 M HCl with 40.00 mL of 0.100 M KOH? Assume that the volumes of the solutions are additive.
A) 0.64 B) 1.64 C) 12.36 D) 13.36 Answer: C
Topic: Section 15.6 Strong Acid - Strong Base Titrations
9) What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous formic acid requires 29.80 mL of 0.3567 M NaOH? Ka =1.8 × 10-4 for formic acid.
A) 2. 06 B) 5. 48 C) 8. 52 D) 11.94 Answer: C
Topic: Section 15.7 Weak Acid – Strong Base Titrations
10) What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous hydrofluoric acid requires 30.00 mL of 0.400 M NaOH? Ka = 6.76 × 10-4 for HF.
A) 1.74 B) 5.75 C) 8.25 D) 12.26 Answer: C
Topic: Section 15.7 Weak Acid – Strong Base Titrations
11) Formic acid (HCO2H, Ka = 1.8 × 10-4) is the principal component in the venom of stinging ants.
What is the molarity of a formic acid solution if 25.00 mL of the formic acid solution requires 29.80 mL of 0.0567 M NaOH to reach the equivalence point?
A) 0.0134 M B) 0.0 476 M C) 0.0567 M D) 0. 0676 M Answer: D
Topic: Section 15.7 Weak Acid – Strong Base Titrations
12) What is the pH of the resulting solution if 25.00 mL of 0.10 M acetic acid is added to 10.00 mL of 0.10 M NaOH? Assume that the volumes of the solutions are additive. Ka = 1.8 × 10-5 for CH3CO2H A) 9. 43
B) 9.08 C) 4.92 D) 4. 57 Answer: D
13) What is the pH of a solution made by mixing 10.00 mL of 0.10 M acetic acid with 10.00 mL of 0.10 M KOH? Assume that the volumes of the solutions are additive. Ka =1.8 × 10-5 for CH3CO2H.
A) 5.28 B) 7.00 C) 8.72 D) 10.02 Answer: C
Topic: Section 15.7 Weak Acid – Strong Base Titrations
14) What is the pH of a solution made by mixing 30.00 mL of 0.10 M acetic acid with 50.00 mL of 0. 100 M KOH? Assume that the volumes of the solutions are additive. Ka = 1.8 × 10-5 for CH3CO2H.
A) 8.26 B) 9.26 C) 11.13 D) 12. 40 Answer: D
Topic: Section 15.7 Weak Acid – Strong Base Titrations
15) Sodium hypochlorite, NaOCl, is the active ingredient in household bleach. What is the concentration of hypochlorite ion if 20.00 mL of bleach requires 32.00 mL of 0.500 M HCl to reach the equivalence point?
Topic: Section 15.8 Weak Base – Strong Acid Titrations
16) What is the pH at the equivalence point of a weak base-strong acid titration if 20.00 mL of NaOCl requires 28.30 mL of 0. 50 M HCl? Ka = 3.0 × 10-8 for HOCl.
Topic: Section 15.8 Weak Base – Strong Acid Titrations
17) What is the pH of the resulting solution if 45 mL of 0.432 M methylamine, CH3NH2, is added to 15 mL of 0.234 M HCl? Assume that the volumes of the solutions are additive. Ka = 2.70 × 10-11 for CH3NH3+.
Topic: Section 15.8 Weak Base – Strong Acid Titrations
18) Calculate the Ksp for silver sulfite if the solubility of Ag2SO3 in pure water is 4.6 × 10-3 g/L.
A) 3.8 × 10-15 B) 1.5 × 10-14 C) 2.4 × 10-10 D) 4.8 × 10-10 Answer: B
Topic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp
19) Calculate the solubility (in g/L) of silver chromate in water at 25°C if the Ksp for Ag2CrO4 is 1.1 × 10-12.
A) 3.5 × 10-4 g/L B) 6.5 × 10-5 g/L C) 2.7 × 10-2 g/L D) 3.4 × 10-2 g/L Answer: B
Topic: Section 15.11 Measuring Ksp and Calculating Solubility from Ksp
20) What is the molar solubility of Mg(OH)2 in a basic solution with a pH of 12.50? Ksp for Mg(OH)2 is 5.61 × 10-12.
A) 1.8 × 10- 10 M B) 5.6 × 10- 9 M C) 2.4 × 10-6 M D) 1.1 × 10-4 M Answer: B
Topic: Section 15.12 Factors That Affect Solubility
21) Calculate the molar solubility of thallium(I) chloride in 0. 40 M NaCl at 25°C. Ksp for TlCl is 1.7 × 10-4.
A) 6.8 × 10-5 M B) 4.2 × 10- 4 M C) 8.2 × 10-3 M D) 1.3 × 10-2 M Answer: B
Topic: Section 15.12 Factors That Affect Solubility