Question 1

Bromocresol green is yellow in its acidic form and blue in its basic form. When is it green?

Accepted Answer

A) at the equivalence point in a titration 
B) in its neutral form 
C) when the solution pH equals its pKa 
D) when the solution pH equals 7 
E) at the midpoint in a titration 
A) at the equivalence point in a titration 
B) in its neutral form 
C) when the solution pH equals its pKa 
D) when the solution pH equals 7 
E) at the midpoint in a titration

Question 2

The pKa of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M. The measured pH was 7.8. What is the pKa of the weak acid?

Accepted Answer

A) 8.0 
B) 7.8 
C) 7.6 
D) 7.0 
E) 7.4 
A) 8.0 
B) 7.8 
C) 7.6 
D) 7.0 
E) 7.4

Question 3

A 25.0 mL solution of quinine was titrated with 1.00 M hydrochloric acid, HCl. It was found that the solution contained 0.125 moles of quinine. What was the pH of the solution after 50.00 mL of the HCl solution were added? Quinine is monobasic with pKb F1F1F1S1F1F1F10 5.10.

Accepted Answer

A) 5.10 
B) 8.90 
C) 8.72 
D) 4.92 
E) 9.08 
A) 5.10 
B) 8.90 
C) 8.72 
D) 4.92 
E) 9.08

Question 4

The most suitable acid-base indicator for a titration of acetic acid with NaOH has ________

Accepted Answer

A) a pKin F1F1F1S1F1F1F10 pKa of the acid. 
B) a pKin F1F1F1S1F1F1F10 pKb of the base. 
C) pKin F1F1F1S1F1F1F10 pH of a sodium acetate solution. 
D) pKin F1F1F1S1F1F1F10 pH of an acetic acid solution. 
E) pKin F1F1F1S1F1F1F10 7.0. 
A) a pKin F1F1F1S1F1F1F10 pKa of the acid. 
B) a pKin F1F1F1S1F1F1F10 pKb of the base. 
C) pKin F1F1F1S1F1F1F10 pH of a sodium acetate solution. 
D) pKin F1F1F1S1F1F1F10 pH of an acetic acid solution. 
E) pKin F1F1F1S1F1F1F10 7.0.

Question 5

Acid-base indicators need to have very intense colors so that a very low concentration is visible. Could there be a problem in using too much indicator?

Accepted Answer

A) No, the colors would just be darker. 
B) No, indicators are inert. 
C) Yes, more indicator requires more extreme pH values to change color. 
D) Yes, the indicator could affect the acid-base chemistry being measured. 
E) No, the colors would just be sharper. 
A) No, the colors would just be darker. 
B) No, indicators are inert. 
C) Yes, more indicator requires more extreme pH values to change color. 
D) Yes, the indicator could affect the acid-base chemistry being measured. 
E) No, the colors would just be sharper.

Question 6

As the pH decreases, the solubility of ________ would increase.

Accepted Answer

A) lead(II) chloride 
B) silver(I) iodate 
C) calcium carbonate 
D) mercury(I) bromide 
E) silver(I) chloride 
A) lead(II) chloride 
B) silver(I) iodate 
C) calcium carbonate 
D) mercury(I) bromide 
E) silver(I) chloride

Question 7

Many metal cations produce aqueous solutions that have a pH different from 7. Which one of the following statements A-D about this phenomenon is not correct?

Accepted Answer

A) For a given metal, the cation with the higher oxidation number will produce more acidic solution, for example, Fe3F1F1F1S1F1F1F10(aq) is more acidic than Fe2F1F1F1S1F1F1F10(aq). 
B) The Lewis acidity of the cation is a good measure of its ability to produce an acidic solution. 
C) Small highly charged main group metal cations, such as Al3F1F1F1S1F1F1F10, produce acidic aqueous solutions. 
D) Alkali metal cations, such as NaF1F1F1S1F1F1F10 and KF1F1F1S1F1F1F10, have a negligible effect on the pH of a solution. 
E) Statements A-D are all correct. 
A) For a given metal, the cation with the higher oxidation number will produce more acidic solution, for example, Fe3F1F1F1S1F1F1F10(aq) is more acidic than Fe2F1F1F1S1F1F1F10(aq). 
B) The Lewis acidity of the cation is a good measure of its ability to produce an acidic solution. 
C) Small highly charged main group metal cations, such as Al3F1F1F1S1F1F1F10, produce acidic aqueous solutions. 
D) Alkali metal cations, such as NaF1F1F1S1F1F1F10 and KF1F1F1S1F1F1F10, have a negligible effect on the pH of a solution. 
E) Statements A-D are all correct.

Question 8

A 0.500 g sample of an unknown substance was titrated with a 0.1 M HCl solution. Another 0.500 g sample of it was titrated with a 0.1 M NaOH solution. The resulting titration curves are illustrated here. Given the following possibilities, what is the sample?

Accepted Answer

A) Na2CO3 
B) NaHCO3 
C) H2CO3 
D) CO2 
E) There is no way to tell. 
A) Na2CO3 
B) NaHCO3 
C) H2CO3 
D) CO2 
E) There is no way to tell.

Question 9

Which of the following compounds contains a coordinate covalent bond?

Accepted Answer

A) Cl2 
B) NH3 
C) H2CF1F1F1S1F1F1F10CH2 
D) Co(H2O)62F1F1F1S1F1F1F10 
E) CH4 
A) Cl2 
B) NH3 
C) H2CF1F1F1S1F1F1F10CH2 
D) Co(H2O)62F1F1F1S1F1F1F10 
E) CH4

Question 10

The pKa of hydrated iron(III) is 2.5, and the pKa of hydrated nickel(II) is 10.0. If 0.1 M solutions of iron(III) nitrate and nickel(II) nitrate are constituted, which one will be more acidic and why?

Accepted Answer

Iron(III) nitrate will be the

Question 11

You have a summer job as an intern in an analytical chemistry laboratory. You are about to titrate a solution of nicotine (pKb F1F1F1S1F1F1F10 6.0), which is a base similar to ammonia, with a standard hydrochloric acid solution. Two pH indicators are available for you to use: thymol blue (pKa F1F1F1S1F1F1F10 3.47) and phenolphthalein (pKb F1F1F1S1F1F1F10 9.4). Which indicator do you select as being the more appropriate one to use?

Accepted Answer

A) Both indicators would work equally well because at the equivalence point the pH of the solution changes very sharply from strongly basic to strongly acidic. 
B) Phenolphthalein is the better choice because it is one of the most commonly used pH indicators. 
C) Neither of these indicators would work because their pKa values are not close to 7.00, which is the pH of the solution at the equivalence point. 
D) Phenolphthalein is the better choice because the sample pH at the equivalence point will be close to the pKa value of 9.4. 
E) Thymol blue is the better choice because the sample pH at the equivalence point will be close to the pKa value of 3.47. 
A) Both indicators would work equally well because at the equivalence point the pH of the solution changes very sharply from strongly basic to strongly acidic. 
B) Phenolphthalein is the better choice because it is one of the most commonly used pH indicators. 
C) Neither of these indicators would work because their pKa values are not close to 7.00, which is the pH of the solution at the equivalence point. 
D) Phenolphthalein is the better choice because the sample pH at the equivalence point will be close to the pKa value of 9.4. 
E) Thymol blue is the better choice because the sample pH at the equivalence point will be close to the pKa value of 3.47.

Question 12

Research with biochemical systems commonly requires buffers because ________

Accepted Answer

A) that's just the way it is. 
B) proteins have a critical pH dependence in their structure and function. 
C) proteins decompose into constituent amino acids outside a certain pH range. 
D) proteins are buffers. 
E) salts are involved. 
A) that's just the way it is. 
B) proteins have a critical pH dependence in their structure and function. 
C) proteins decompose into constituent amino acids outside a certain pH range. 
D) proteins are buffers. 
E) salts are involved.

Question 13

A solution of hydrofluoric acid (0.15 M, 25.00 mL) was titrated with 0.10 M sodium hydroxide (Ka of hydrofluoric acid F1F1F1S1F1F1F10 7.20 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F104). What is the pH at the equivalence point?

Accepted Answer

A) 5.12 
B) 6.04 
C) 7.00 
D) 7.96 
E) 8.88 
A) 5.12 
B) 6.04 
C) 7.00 
D) 7.96 
E) 8.88

Question 14

Which of the following would be the best choice for preparing a buffer with a pH F1F1F1S1F1F1F10 3.5?

Accepted Answer

A) a solution of formic acid and sodium formate, Ka F1F1F1S1F1F1F10 1.8 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F104 
B) a solution of acetic acid and sodium acetate, Ka F1F1F1S1F1F1F10 1.8 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F105 
C) a solution of hypochlorous acid and sodium hypochlorite, Ka F1F1F1S1F1F1F10 3.5 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F108 
D) a solution of boric acid and sodium borate, Ka F1F1F1S1F1F1F10 5.8 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1010 
E) All of these solutions would be equally good choices for making this buffer. 
A) a solution of formic acid and sodium formate, Ka F1F1F1S1F1F1F10 1.8 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F104 
B) a solution of acetic acid and sodium acetate, Ka F1F1F1S1F1F1F10 1.8 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F105 
C) a solution of hypochlorous acid and sodium hypochlorite, Ka F1F1F1S1F1F1F10 3.5 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F108 
D) a solution of boric acid and sodium borate, Ka F1F1F1S1F1F1F10 5.8 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1010 
E) All of these solutions would be equally good choices for making this buffer.

Question 15

Describe how you would prepare a buffer with pH 3.60 using 100 mL of a 1.0 M nitrous acid solution and sodium nitrite (the Ka for nitrous acid is 4.0 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F104). Assume a minimal volume change upon addition of sodium nitrite.

Accepted Answer

For a pH of 3.60, the ratio of conjugate

Question 16

The following titration curve is most likely to be associated with ________

Accepted Answer

A) the titration of a strong acid with a strong base titrant. 
B) the titration of a weak acid with a strong base titrant. 
C) the titration of a strong base with a strong acid titrant. 
D) the titration of a weak base with a strong acid titrant. 
A) the titration of a strong acid with a strong base titrant. 
B) the titration of a weak acid with a strong base titrant. 
C) the titration of a strong base with a strong acid titrant. 
D) the titration of a weak base with a strong acid titrant.

Question 17

One brand of extra-strength antacid tablets contains 750 mg of calcium carbonate (100 g/mol) in each tablet. Stomach acid is essentially a hydrochloric acid solution. Is so much calcium carbonate really needed to neutralize stomach acid? Calculate the volume of stomach acid with a pH of 1.0 that one of these tablets could neutralize, and compare that value with the normal volume of stomach fluid, which usually is about 100 mL. One tablet can neutralize ________ mL of stomach acid at a pH of 1.0.

Accepted Answer

A) 75 
B) 150 
C) 250 
D) 15 
E) 7.5 
A) 75 
B) 150 
C) 250 
D) 15 
E) 7.5

Question 18

Which of the following compounds would not have a pH-dependent solubility?

Accepted Answer

A) Mg(OH)2 
B) PbS 
C) AgI 
D) Na2O 
E) PbCl2 
A) Mg(OH)2 
B) PbS 
C) AgI 
D) Na2O 
E) PbCl2

Question 19

What is the solubility of silver iodide in a solution containing 0.20 M sodium iodide? The Ksp value for silver iodide is 1.5 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1016.

Accepted Answer

A) 7.5 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1016 M 
B) 1.2 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F108 M 
C) 3.0 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1017 M 
D) 0.20 M 
E) 2.1 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1010 M 
A) 7.5 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1016 M 
B) 1.2 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F108 M 
C) 3.0 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1017 M 
D) 0.20 M 
E) 2.1 F1F1F1S1F1F1F10 10F1F1F1S1F1F1F1010 M

Question 20

Identify the Lewis acid in the following reaction:

Accepted Answer

A) BF3 
B) FF1F1F1S1F1F1F10 
C) BF4F1F1F1S1F1F1F10 
D) None of these is an acid. 
E) All of these are acids. 
A) BF3 
B) FF1F1F1S1F1F1F10 
C) BF4F1F1F1S1F1F1F10 
D) None of these is an acid. 
E) All of these are acids.

Bromocresol green is yellow in its acidic form and blue in its basic form. When is it green?

The pK_a of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M. The measured pH was 7.8. What is the pK_a of the weak acid?

A 25.0 mL solution of quinine was titrated with 1.00 M hydrochloric acid, HCl. It was found that the solution contained 0.125 moles of quinine. What was the pH of the solution after 50.00 mL of the HCl solution were added? Quinine is monobasic with pK_b  5.10.

The most suitable acid-base indicator for a titration of acetic acid with NaOH has ________

Acid-base indicators need to have very intense colors so that a very low concentration is visible. Could there be a problem in using too much indicator?

As the pH decreases, the solubility of ________ would increase.

Many metal cations produce aqueous solutions that have a pH different from 7. Which one of the following statements A-D about this phenomenon is not correct?

A 0.500 g sample of an unknown substance was titrated with a 0.1 M HCl solution. Another 0.500 g sample of it was titrated with a 0.1 M NaOH solution. The resulting titration curves are illustrated here. Given the following possibilities, what is the sample?

Which of the following compounds contains a coordinate covalent bond?

The pK_a of hydrated iron(III) is 2.5, and the pK_a of hydrated nickel(II) is 10.0. If 0.1 M solutions of iron(III) nitrate and nickel(II) nitrate are constituted, which one will be more acidic and why?

Research with biochemical systems commonly requires buffers because ________

A solution of hydrofluoric acid (0.15 M, 25.00 mL) was titrated with 0.10 M sodium hydroxide (K_a of hydrofluoric acid  7.20  10^⁴). What is the pH at the equivalence point?

Which of the following would be the best choice for preparing a buffer with a pH  3.5?

Describe how you would prepare a buffer with pH 3.60 using 100 mL of a 1.0 M nitrous acid solution and sodium nitrite (the K_a for nitrous acid is 4.0  10^⁴). Assume a minimal volume change upon addition of sodium nitrite.

The following titration curve is most likely to be associated with ________

Which of the following compounds would not have a pH-dependent solubility?

What is the solubility of silver iodide in a solution containing 0.20 M sodium iodide? The K_sp value for silver iodide is 1.5  10^¹⁶.

Identify the Lewis acid in the following reaction:

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

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Exam 16: Additional Aqueous Equilibria: Chemistry and the Oceans

Bromocresol green is yellow in its acidic form and blue in its basic form. When is it green?

The pKa of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M. The measured pH was 7.8. What is the pKa of the weak acid?

A 25.0 mL solution of quinine was titrated with 1.00 M hydrochloric acid, HCl. It was found that the solution contained 0.125 moles of quinine. What was the pH of the solution after 50.00 mL of the HCl solution were added? Quinine is monobasic with pKb  5.10.

The most suitable acid-base indicator for a titration of acetic acid with NaOH has ________

Acid-base indicators need to have very intense colors so that a very low concentration is visible. Could there be a problem in using too much indicator?

As the pH decreases, the solubility of ________ would increase.

Many metal cations produce aqueous solutions that have a pH different from 7. Which one of the following statements A-D about this phenomenon is not correct?

A 0.500 g sample of an unknown substance was titrated with a 0.1 M HCl solution. Another 0.500 g sample of it was titrated with a 0.1 M NaOH solution. The resulting titration curves are illustrated here. Given the following possibilities, what is the sample?

Which of the following compounds contains a coordinate covalent bond?

The pKa of hydrated iron(III) is 2.5, and the pKa of hydrated nickel(II) is 10.0. If 0.1 M solutions of iron(III) nitrate and nickel(II) nitrate are constituted, which one will be more acidic and why?

Research with biochemical systems commonly requires buffers because ________

A solution of hydrofluoric acid (0.15 M, 25.00 mL) was titrated with 0.10 M sodium hydroxide (Ka of hydrofluoric acid  7.20  104). What is the pH at the equivalence point?

Which of the following would be the best choice for preparing a buffer with a pH  3.5?

Describe how you would prepare a buffer with pH 3.60 using 100 mL of a 1.0 M nitrous acid solution and sodium nitrite (the Ka for nitrous acid is 4.0  104). Assume a minimal volume change upon addition of sodium nitrite.

The following titration curve is most likely to be associated with ________

Which of the following compounds would not have a pH-dependent solubility?

What is the solubility of silver iodide in a solution containing 0.20 M sodium iodide? The Ksp value for silver iodide is 1.5  1016.

Identify the Lewis acid in the following reaction:

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

The pK_a of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M. The measured pH was 7.8. What is the pK_a of the weak acid?

A 25.0 mL solution of quinine was titrated with 1.00 M hydrochloric acid, HCl. It was found that the solution contained 0.125 moles of quinine. What was the pH of the solution after 50.00 mL of the HCl solution were added? Quinine is monobasic with pK_b  5.10.

The pK_a of hydrated iron(III) is 2.5, and the pK_a of hydrated nickel(II) is 10.0. If 0.1 M solutions of iron(III) nitrate and nickel(II) nitrate are constituted, which one will be more acidic and why?

A solution of hydrofluoric acid (0.15 M, 25.00 mL) was titrated with 0.10 M sodium hydroxide (K_a of hydrofluoric acid  7.20  10^⁴). What is the pH at the equivalence point?

Describe how you would prepare a buffer with pH 3.60 using 100 mL of a 1.0 M nitrous acid solution and sodium nitrite (the K_a for nitrous acid is 4.0  10^⁴). Assume a minimal volume change upon addition of sodium nitrite.

What is the solubility of silver iodide in a solution containing 0.20 M sodium iodide? The K_sp value for silver iodide is 1.5  10^¹⁶.