Question 1

If 0.50 L of a buffer containing 1.0 mol H2PO4− and 1.0 mol HPO42− is diluted to a volume of 5.0 L, the pH

Accepted Answer

A)  increases by 1. 
B)  decreases by 1. 
C)  increases by 10. 
D)  decreases by 10. 
E)  remains unchanged. 
A)  increases by 1. 
B)  decreases by 1. 
C)  increases by 10. 
D)  decreases by 10. 
E)  remains unchanged. E

Question 2

What is the minimum concentration of Cd2+ required to begin precipitating Cd(OH)2(s) in a solution buffered at pH 10.83? The Ksp of Cd(OH)2 is 5.3 × 10-15 and Kw = 1.01 × 10-14.

Accepted Answer

A)  3.4 × 10-4 M 
B)  3.6 × 10-4 M 
C)  7.8 × 10-12 M 
D)  1.2 × 10-8 M 
E)  4.5 × 10-17 M 
A)  3.4 × 10-4 M 
B)  3.6 × 10-4 M 
C)  7.8 × 10-12 M 
D)  1.2 × 10-8 M 
E)  4.5 × 10-17 M D

Question 3

When mixed in appropriate amounts, each of the following mixtures can produce an effective buffer solution except _____.

Accepted Answer

A)  HCl and NaH2PO4 
B)  Na2HPO4 and Na3PO4 
C)  NaHCO3 and Na2CO3 
D)  NaH2PO4 and Na2HPO4 
E)  NaOH and NaF 
A)  HCl and NaH2PO4 
B)  Na2HPO4 and Na3PO4 
C)  NaHCO3 and Na2CO3 
D)  NaH2PO4 and Na2HPO4 
E)  NaOH and NaF E

Question 4

A solution containing 10. mmol of CO32−and 5.0 mmol of HCO3−is titrated with 1.1 M HCl. What volume of HCl must be added to reach the first equivalence point? (1 mmol = 0.001 mol)

Accepted Answer

A)  24.1 mL 
B)  4.5 mL 
C)  9.1 mL 
D)  19.1 mL 
E)  14.1 mL 
A)  24.1 mL 
B)  4.5 mL 
C)  9.1 mL 
D)  19.1 mL 
E)  14.1 mL

Question 5

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid, HC3H5O2, with strong base?

Accepted Answer

A)  alizarin yellow (transition pH range: 10.0-12.0) 
B)  methyl red (transition pH range: 4.2-6.3) 
C)  methyl orange (transition pH range: 3.1-4.4) 
D)  thymol blue (transition pH range: 8.0-9.6) 
E)  bromothymol blue (transition pH range: 6.2-7.6) 
A)  alizarin yellow (transition pH range: 10.0-12.0) 
B)  methyl red (transition pH range: 4.2-6.3) 
C)  methyl orange (transition pH range: 3.1-4.4) 
D)  thymol blue (transition pH range: 8.0-9.6) 
E)  bromothymol blue (transition pH range: 6.2-7.6)

Question 6

A 5.0 × 10-4 M solution of MnSO4 is gradually made more basic by adding NaOH. At what pH will manganese(II) hydroxide begin to precipitate? The Ksp of Mn(OH)2 is 2.0 × 10-13 and Kw = 1.01 × 10-14.

Accepted Answer

A)  4.60 
B)  9.57 
C)  4.70 
D)  9.30 
E)  9.40 
A)  4.60 
B)  9.57 
C)  4.70 
D)  9.30 
E)  9.40

Question 7

A 1.0 liter solution contains 0.25 M hydrogen fluoride (HF) and 0.38 M sodium fluoride (NaF). What is the pH of this solution? (Ka for HF is 7.2 × 10-4)

Accepted Answer

A)  3.14 
B)  3.32 
C)  2.96 
D)  0.18 
E)  10.68 
A)  3.14 
B)  3.32 
C)  2.96 
D)  0.18 
E)  10.68

Question 8

What is the pH of a solution made by combining 134 mL of 0.26 M NaC2H3O2 with 211 mL of 0.31 M HC2H3O2? The Ka of acetic acid is 1.75 × 10-5.

Accepted Answer

A)  4.47 
B)  5.04 
C)  5.52 
D)  4.42 
E)  4.97 
A)  4.47 
B)  5.04 
C)  5.52 
D)  4.42 
E)  4.97

Question 9

What is the concentration of silver(I) ion in a saturated solution of silver(I) carbonate containing 0.0072 M Na2CO3? For Ag2CO3, Ksp = 8.6 × 10-12.

Accepted Answer

A)  6.0 × 10-4 M 
B)  2.0 × 10-9 M 
C)  8.0 × 10-9 M 
D)  3.5 × 10-5 M 
E)  8.0 × 10-4 M 
A)  6.0 × 10-4 M 
B)  2.0 × 10-9 M 
C)  8.0 × 10-9 M 
D)  3.5 × 10-5 M 
E)  8.0 × 10-4 M

Question 10

How many moles of solid NaF would have to be added to 1.0 L of 1.85 M HF solution to achieve a buffer of pH 3.35? Assume there is no volume change. (Ka for HF = 7.2 × 10-4)

Accepted Answer

A)  3.0 
B)  0.38 
C)  0.87 
D)  1.0 
E)  1.6 
A)  3.0 
B)  0.38 
C)  0.87 
D)  1.0 
E)  1.6

Question 11

What is the value of the dissociation constant, Kdissociation, for the complex ion Zn(NH3)42+? (Kf = 2.9 × 109)

Accepted Answer

A)  2.9 × 10-5 
B)  7.3 × 108 
C)  2.9 × 109 
D)  2.3 × 102 
E)  3.4 × 10-10 
A)  2.9 × 10-5 
B)  7.3 × 108 
C)  2.9 × 109 
D)  2.3 × 102 
E)  3.4 × 10-10

Question 12

What is the minimum mass of Na2CO3 (molar mass = 105.990 g/mol) that must be added to 43.4 mL of a 1.0 × 10-4 M AgNO3 solution in order for precipitation to occur? The Ksp of Ag2CO3 is 8.6 × 10-12. Assume no volume change occurs upon addition of Na2CO3.

Accepted Answer

A)  4.6 × 10-4 g 
B)  3.1 × 10-4 g 
C)  2.3 × 10-4 g 
D)  4.0 × 10-7 g 
E)  4.0 × 10-3 g 
A)  4.6 × 10-4 g 
B)  3.1 × 10-4 g 
C)  2.3 × 10-4 g 
D)  4.0 × 10-7 g 
E)  4.0 × 10-3 g

Question 13

Which is the best colored indicator to use in the titration of 0.1 M CH3CO2H(aq) with NaOH(aq)? Why? (Ka of CH3CO2H = 1.8 × 10-5, Kb of CH3CO2- = 5.6 × 10-10)$$\begin{array} { l l } 
\text { Indicator } & \mathrm { p } K _ { \mathrm { a } } \
\hline \text { Bromcresol Green } & 4.8 \
\text { Bromthymol Blue } & 6.8 \
\text { Phenolphthalein } & 9.2
\end{array}$$

Accepted Answer

A)  Bromcresol Green. The equivalence point for a weak acid titration occurs at low pH. 
B)  Bromthymol Blue. The pH at the equivalence point is 7.0. 
C)  Bromcresol Green. The pKa of CH3CO2H and the pKa of the indicator are similar. 
D)  Phenolphthalein. The pKa of CH3CO2- and the pKb of the indicator are similar. 
E)  Phenolphthalein. The pH at the equivalence point is near the pKa of the indicator. 
A)  Bromcresol Green. The equivalence point for a weak acid titration occurs at low pH. 
B)  Bromthymol Blue. The pH at the equivalence point is 7.0. 
C)  Bromcresol Green. The pKa of CH3CO2H and the pKa of the indicator are similar. 
D)  Phenolphthalein. The pKa of CH3CO2- and the pKb of the indicator are similar. 
E)  Phenolphthalein. The pH at the equivalence point is near the pKa of the indicator.

Question 14

What is the molar solubility of silver(I) iodide at 25°C? The solubility product constant for silver(I) iodide is 8.3 × 10-17 at 25°C.

Accepted Answer

A)  9.1 × 10-9 M 
B)  4.2 × 10-17 M 
C)  4.8 × 10-5 M 
D)  2.7 × 10-6 M 
E)  8.3 × 10-17 M 
A)  9.1 × 10-9 M 
B)  4.2 × 10-17 M 
C)  4.8 × 10-5 M 
D)  2.7 × 10-6 M 
E)  8.3 × 10-17 M

Question 15

Hyperventilation can cause your blood pH to rise. One way to lower your blood pH is to breathe into a paper bag, thus recycling the air you exhale. Why does this procedure lower your blood pH?

Accepted Answer

By breathing recycled air, you increase

Question 16

What color change is exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide?

Accepted Answer

A)  Colorless to pink 
B)  Pink to colorless 
C)  Green to yellow 
D)  Yellow to blue 
E)  Blue to yellow 
A)  Colorless to pink 
B)  Pink to colorless 
C)  Green to yellow 
D)  Yellow to blue 
E)  Blue to yellow

Question 17

What is the pH of a buffer composed of 0.35 M H2PO4-(aq) and 0.65 M HPO42-(aq)? (Ka of H2PO4- is 6.2 × 10-8)

Accepted Answer

A)  6.94 
B)  7.21 
C)  7.48 
D)  7.73 
E)  9.06 
A)  6.94 
B)  7.21 
C)  7.48 
D)  7.73 
E)  9.06

Question 18

The following anions can be separated by precipitation as silver salts: Cl-, Br-, I-, and CrO42-. If silver ions (Ag+) are added to a solution containing the four anions that are at concentrations of 0.10 M, in what order will they precipitate? $$\begin{array} { l l } 
\text { Compound } & K _ { \mathrm { sp } } \
\hline \mathrm { AgCl } & 1.8 \times 10 ^ { - 10 } \
\mathrm { Ag } _ { 2 } \mathrm { CrO } _ { 4 } & 1.1 \times 10 ^ { - 12 } \
\mathrm { AgBr } & 5.4 \times 10 ^ { - 13 } \
\mathrm { AgI } & 8.5 \times 10 ^ { - 17 }
\end{array}$$

Accepted Answer

A)  AgCl ? Ag2CrO4 ? AgBr ? AgI 
B)  AgI? AgBr ? Ag2CrO4 ? AgCl 
C)  Ag2CrO4 ? AgCl ?AgBr ?AgI 
D)  Ag2CrO4 ? AgI ? AgBr ? AgCl 
E)  AgI ? AgBr ? AgCl ?Ag2CrO4 
A)  AgCl ? Ag2CrO4 ? AgBr ? AgI 
B)  AgI? AgBr ? Ag2CrO4 ? AgCl 
C)  Ag2CrO4 ? AgCl ?AgBr ?AgI 
D)  Ag2CrO4 ? AgI ? AgBr ? AgCl 
E)  AgI ? AgBr ? AgCl ?Ag2CrO4

Question 19

Which of the following mathematical expressions is the Henderson-Hasselbalch equation?

Accepted Answer

A)  $\mathrm { p } K _ { \mathrm { a } } = \mathrm { pH } + \log \left( \frac { [ \text { conjugate base } ] } { [ \text { acid } ] } \right)$ 
B)  $\mathrm { pH } = \mathbf { p } K _ { \mathrm { a } } + \log \left( \frac { \left[ \mathrm { OH } ^ { - } \right] } { \left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { + } \right] } \right)$ 
C)  $\mathrm { pH } = \mathrm { p } K _ { \mathrm { a } } + \log \left( \frac { [ \text { acid } ] } { [ \text { conjugate base } ] } \right)$ 
D)  $\mathrm { p } K _ { \mathrm { a } } = \mathrm { pH } + \log \left( \frac { \left[ \mathrm { OH } ^ { - } \right] } { \left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { + } \right] } \right)$ 
E)  $\mathrm { pH } = \mathbf { p } K _ { \mathrm { a } } + \log \left( \frac { [ \text { conjugate base } ] } { [ \text { acid } ] } \right)$ 
A)  $\mathrm { p } K _ { \mathrm { a } } = \mathrm { pH } + \log \left( \frac { [ \text { conjugate base } ] } { [ \text { acid } ] } \right)$ 
B)  $\mathrm { pH } = \mathbf { p } K _ { \mathrm { a } } + \log \left( \frac { \left[ \mathrm { OH } ^ { - } \right] } { \left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { + } \right] } \right)$ 
C)  $\mathrm { pH } = \mathrm { p } K _ { \mathrm { a } } + \log \left( \frac { [ \text { acid } ] } { [ \text { conjugate base } ] } \right)$ 
D)  $\mathrm { p } K _ { \mathrm { a } } = \mathrm { pH } + \log \left( \frac { \left[ \mathrm { OH } ^ { - } \right] } { \left[ \mathrm { H } _ { 3 } \mathrm { O } ^ { + } \right] } \right)$ 
E)  $\mathrm { pH } = \mathbf { p } K _ { \mathrm { a } } + \log \left( \frac { [ \text { conjugate base } ] } { [ \text { acid } ] } \right)$

Question 20

To make a buffer with a pH of 8.00, you should use a weak acid with a Ka close to _______.

Accepted Answer

Exam 18: Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

If 0.50 L of a buffer containing 1.0 mol H2PO4− and 1.0 mol HPO42− is diluted to a volume of 5.0 L, the pH

What is the minimum concentration of Cd2+ required to begin precipitating Cd(OH)2(s) in a solution buffered at pH 10.83? The Ksp of Cd(OH)2 is 5.3 × 10-15 and Kw = 1.01 × 10-14.

When mixed in appropriate amounts, each of the following mixtures can produce an effective buffer solution except _____.

A solution containing 10. mmol of CO32−and 5.0 mmol of HCO3−is titrated with 1.1 M HCl. What volume of HCl must be added to reach the first equivalence point? (1 mmol = 0.001 mol)

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid, HC3H5O2, with strong base?

A 5.0 × 10-4 M solution of MnSO4 is gradually made more basic by adding NaOH. At what pH will manganese(II) hydroxide begin to precipitate? The Ksp of Mn(OH)2 is 2.0 × 10-13 and Kw = 1.01 × 10-14.

A 1.0 liter solution contains 0.25 M hydrogen fluoride (HF) and 0.38 M sodium fluoride (NaF). What is the pH of this solution? (Ka for HF is 7.2 × 10-4)

What is the pH of a solution made by combining 134 mL of 0.26 M NaC2H3O2 with 211 mL of 0.31 M HC2H3O2? The Ka of acetic acid is 1.75 × 10-5.

What is the concentration of silver(I) ion in a saturated solution of silver(I) carbonate containing 0.0072 M Na2CO3? For Ag2CO3, Ksp = 8.6 × 10-12.

How many moles of solid NaF would have to be added to 1.0 L of 1.85 M HF solution to achieve a buffer of pH 3.35? Assume there is no volume change. (Ka for HF = 7.2 × 10-4)

What is the value of the dissociation constant, Kdissociation, for the complex ion Zn(NH3)42+? (Kf = 2.9 × 109)

What is the minimum mass of Na2CO3 (molar mass = 105.990 g/mol) that must be added to 43.4 mL of a 1.0 × 10-4 M AgNO3 solution in order for precipitation to occur? The Ksp of Ag2CO3 is 8.6 × 10-12. Assume no volume change occurs upon addition of Na2CO3.

Which is the best colored indicator to use in the titration of 0.1 M CH3CO2H(aq) with NaOH(aq)? Why? (Ka of CH3CO2H = 1.8 × 10-5, Kb of CH3CO2- = 5.6 × 10-10) Indicator Bromcresol Green 4.8 Bromthymol Blue 6.8 Phenolphthalein 9.2

What is the molar solubility of silver(I) iodide at 25°C? The solubility product constant for silver(I) iodide is 8.3 × 10-17 at 25°C.

Hyperventilation can cause your blood pH to rise. One way to lower your blood pH is to breathe into a paper bag, thus recycling the air you exhale. Why does this procedure lower your blood pH?

What color change is exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide?

What is the pH of a buffer composed of 0.35 M H2PO4-(aq) and 0.65 M HPO42-(aq)? (Ka of H2PO4- is 6.2 × 10-8)

The following anions can be separated by precipitation as silver salts: Cl-, Br-, I-, and CrO42-. If silver ions (Ag+) are added to a solution containing the four anions that are at concentrations of 0.10 M, in what order will they precipitate? Compound 1.8\times1 1.1\times1 5.4\times1 8.5\times1

Which of the following mathematical expressions is the Henderson-Hasselbalch equation?

To make a buffer with a pH of 8.00, you should use a weak acid with a Ka close to _______.

Basic Concepts of Chemistry

Lets Review: the Tools of Quantitative Chemistry

Atoms, Molecules, and Ions

Chemical Reactions

Stoichiometry: Quantitative Information About Chemical Reactions

Principles of Chemical Reactivity: Energy and Chemical Reactions

The Structure of Atoms

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Bonding and Molecular Structure

Bonding and Molecular Structure Orbital Hybridization and Molecular Orbitals

Gases and Their Properties

Intermolecular Forces and Liquids

The Solid State

Solutions and Their Behavior

Chemical Kinetics: the Rates of Chemical Reactions

Principles of Chemical Reactivity: Equilibria

Principles of Chemical Reactivity: the Chemistry of Acids and Bases

Principles of Chemical Reactivity: Entropy and Free Energy

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Environmental Chemistry: Earths Environment, Energy, and Sustainability

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Carbon: Not Just Another Element

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If 0.50 L of a buffer containing 1.0 mol H₂PO₄− and 1.0 mol HPO₄²⁻ is diluted to a volume of 5.0 L, the pH

What is the minimum concentration of Cd²⁺ required to begin precipitating Cd(OH)₂(s) in a solution buffered at pH 10.83? The K_sp of Cd(OH)₂ is 5.3 × 10^-15 and K_w = 1.01 × 10^-14.

A solution containing 10. mmol of CO₃²⁻and 5.0 mmol of HCO₃−is titrated with 1.1 M HCl. What volume of HCl must be added to reach the first equivalence point? (1 mmol = 0.001 mol)

Which of the following indicators is most suitable for the titration of a 25.00-mL sample of 0.140 M propionic acid, HC₃H₅O₂, with strong base?

A 5.0 × 10^-4 M solution of MnSO₄ is gradually made more basic by adding NaOH. At what pH will manganese(II) hydroxide begin to precipitate? The K_sp of Mn(OH)₂ is 2.0 × 10^-13 and K_w = 1.01 × 10^-14.

A 1.0 liter solution contains 0.25 M hydrogen fluoride (HF) and 0.38 M sodium fluoride (NaF). What is the pH of this solution? (K_a for HF is 7.2 × 10^-4)

What is the pH of a solution made by combining 134 mL of 0.26 M NaC₂H₃O₂ with 211 mL of 0.31 M HC₂H₃O₂? The K_a of acetic acid is 1.75 × 10^-5.

What is the concentration of silver(I) ion in a saturated solution of silver(I) carbonate containing 0.0072 M Na₂CO₃? For Ag₂CO₃, K_sp = 8.6 × 10^-12.

How many moles of solid NaF would have to be added to 1.0 L of 1.85 M HF solution to achieve a buffer of pH 3.35? Assume there is no volume change. (K_a for HF = 7.2 × 10^-4)

What is the value of the dissociation constant, K_dissociation, for the complex ion Zn(NH₃)₄²⁺? (K_f = 2.9 × 10⁹)

What is the minimum mass of Na₂CO₃ (molar mass = 105.990 g/mol) that must be added to 43.4 mL of a 1.0 × 10^-4 M AgNO₃ solution in order for precipitation to occur? The K_sp of Ag₂CO₃ is 8.6 × 10^-12. Assume no volume change occurs upon addition of Na₂CO₃.

Which is the best colored indicator to use in the titration of 0.1 M CH₃CO₂H(aq) with NaOH(aq)? Why? (K_a of CH₃CO₂H = 1.8 × 10^-5, K_b of CH₃CO₂^- = 5.6 × 10^-10) Indicator Bromcresol Green 4.8 Bromthymol Blue 6.8 Phenolphthalein 9.2

What is the molar solubility of silver(I) iodide at 25°C? The solubility product constant for silver(I) iodide is 8.3 × 10^-17 at 25°C.

What is the pH of a buffer composed of 0.35 M H₂PO₄^-(aq) and 0.65 M HPO₄^2-(aq)? (K_a of H₂PO₄^- is 6.2 × 10^-8)

To make a buffer with a pH of 8.00, you should use a weak acid with a K_a close to _______.