Question 1

What is the [H3O+] concentration of a solution with a pH of 8.75?

Accepted Answer

A)  1.8 x 10 - 9M 
B)  9.4 x 10 - 1M 
C)  8.7 x 10-5M 
D)  5.6 x 108M 
E)  This is a basic solution, [H3O+] cannot be determined. 
A)  1.8 x 10 - 9M 
B)  9.4 x 10 - 1M 
C)  8.7 x 10-5M 
D)  5.6 x 108M 
E)  This is a basic solution, [H3O+] cannot be determined. A

Question 2

The dihydrogen phosphate ion, H2PO4 - , can behave as both an acid and as a base. What is the chemical formula of the conjugate acid of dihydrogen phosphate? What is the chemical formula of the conjugate base of dihydrogen phosphate?

Accepted Answer

A)  conjugate acid = H3PO4 conjugate base = HPO42 - 
B)  conjugate acid = H2PO4+ conjugate base = H2PO42 - 
C)  conjugate acid = HPO42 -  conjugate base = H3PO4 
D)  conjugate acid = H3PO4 conjugate base = PO43 - 
E)  none of these 
A)  conjugate acid = H3PO4 conjugate base = HPO42 - 
B)  conjugate acid = H2PO4+ conjugate base = H2PO42 - 
C)  conjugate acid = HPO42 -  conjugate base = H3PO4 
D)  conjugate acid = H3PO4 conjugate base = PO43 - 
E)  none of these A

Question 3

A strong acid is added to water. Which of the following will be true?

Accepted Answer

A)  [H3O+] increases, [OH - ] decreases, pH increases 
B)  [H3O+] decreases, [OH - ] increases, pH decreases 
C)  [H3O+] decreases, [OH - ] decreases, pH decreases 
D)  [H3O+] increases, [OH - ] increases, pH increases 
E)  none of these 
A)  [H3O+] increases, [OH - ] decreases, pH increases 
B)  [H3O+] decreases, [OH - ] increases, pH decreases 
C)  [H3O+] decreases, [OH - ] decreases, pH decreases 
D)  [H3O+] increases, [OH - ] increases, pH increases 
E)  none of these E

Question 4

What is the OH- ion concentration in a 0.200 M NaOAc solution?
(HOAc: Ka = 1.8 x 10-5)

Accepted Answer

A)  1.1 x 10-10 
B)  5.7 x 10-10 
C)  1.8 x 10-6 
D)  1.1 x 10-5 
E)  1.3 x 10-3 
A)  1.1 x 10-10 
B)  5.7 x 10-10 
C)  1.8 x 10-6 
D)  1.1 x 10-5 
E)  1.3 x 10-3

Question 5

What is the Kb for methylamine (CH3NH2) if a 0.10 M solution of this weak base is 6.8% ionized?

Accepted Answer

A)  5.0 x 10-4 
B)  0.068 
C)  4.6 x 10-5 
D)  2.0 x 103 
E)  1.0 
A)  5.0 x 10-4 
B)  0.068 
C)  4.6 x 10-5 
D)  2.0 x 103 
E)  1.0

Question 6

What is the pH of a 0.10 M succinic acid, H2Sc, solution if we assume that H2Sc is a weak acid that undergoes stepwise dissociation?
H2Sc(aq) + H2O(l)   H3O+(aq) + HSc-(aq) &emsp; Ka1 = 6.9 x 10-5
HSc-(aq) + H2O(l)   H3O+(aq) + Sc2-(aq) &emsp; Ka2 = 2.5 x 10-6

Accepted Answer

A)  2.1 
B)  2.6 
C)  3.3 
D)  4.2 
E)  5.6 
A)  2.1 
B)  2.6 
C)  3.3 
D)  4.2 
E)  5.6

Question 7

Which of the following is the conjugate base of a strong acid?

Accepted Answer

A)  OH- 
B)  HSO4- 
C)  NH2- 
D)  S2- 
E)  H3O+ 
A)  OH- 
B)  HSO4- 
C)  NH2- 
D)  S2- 
E)  H3O+

Question 8

Which of the following statements should be true for a 1.0x 10 - 4 M solution of a strong acid HBr?

Accepted Answer

A)  [Br - ] >> [H3O+] 
B)  pH = 4.00 
C)  [HBr] = 1.0 x 10 - 4M 
D)  [Br  - ] = [HBr] 
E)  pH = 1.00 
A)  [Br - ] >> [H3O+] 
B)  pH = 4.00 
C)  [HBr] = 1.0 x 10 - 4M 
D)  [Br  - ] = [HBr] 
E)  pH = 1.00

Question 9

A solution is prepared by dissolving 1.0 x 10-4 moles of HOBr in water and diluting to 1.00 L. What is the pH of this solution? (HOBr: Ka = 2 x 10-9)

Accepted Answer

A)  1.3 
B)  5.3 
C)  6.3 
D)  8.7 
E)  12.7 
A)  1.3 
B)  5.3 
C)  6.3 
D)  8.7 
E)  12.7

Question 10

Using data from the previous problem, what fraction of the HSc- formed in the first step of the dissociation of succinic acid goes on to dissociate to form Sc2- ions in the second step, and what does this lead us to conclude?

Accepted Answer

A)  None of the HSc- ions dissociate further, and the stepwise dissociation assumption is legitimate. 
B)  Less than 1% of the HSc- ion dissociate to form Sc2- ions, and the stepwise dissociation assumption is legitimate. 
C)  Between 1 and 5% of the HSc- ions dissociate, and the stepwise dissociation assumption is legitimate. 
D)  Between 5 and 20% of the HSc- ions dissociate, and the stepwise dissociation assumption is legitimate. 
E)  Between 5 and 20% of the HSc- ions dissociate, and the stepwise dissociation assumption is not legitimate. 
A)  None of the HSc- ions dissociate further, and the stepwise dissociation assumption is legitimate. 
B)  Less than 1% of the HSc- ion dissociate to form Sc2- ions, and the stepwise dissociation assumption is legitimate. 
C)  Between 1 and 5% of the HSc- ions dissociate, and the stepwise dissociation assumption is legitimate. 
D)  Between 5 and 20% of the HSc- ions dissociate, and the stepwise dissociation assumption is legitimate. 
E)  Between 5 and 20% of the HSc- ions dissociate, and the stepwise dissociation assumption is not legitimate.

Question 11

Which of the following statements is true?

Accepted Answer

A)  H2O is a weaker acid than NH3. 
B)  PH3 is a weaker acid than NH3. 
C)  OH- is a weaker base than H2O. 
D)  NH2- is the conjugate acid of NH3. 
E)  ClO- is a stronger base than ClO4-. 
A)  H2O is a weaker acid than NH3. 
B)  PH3 is a weaker acid than NH3. 
C)  OH- is a weaker base than H2O. 
D)  NH2- is the conjugate acid of NH3. 
E)  ClO- is a stronger base than ClO4-.

Question 12

If the strength of the following acids increases from left to right
CH3NH2 3NH3+ 6H5NH3 + 6H5CO2H < HCl

The order of increasing base strength, reading from left to right, must be:

Accepted Answer

A)  CH3NH- 3NH2 6H5NH2 6H5CO2- - 
B)  Cl- 6H5CO2- 6H5NH2 3NH2 3NH- 
C)  C6H5NH2 3NH2 - 6H5CO2- 3NH- 
D)  CH3NH- 6H5CO2- - 3NH2 6H5NH2 
E)  none of the above 
A)  CH3NH- 3NH2 6H5NH2 6H5CO2- - 
B)  Cl- 6H5CO2- 6H5NH2 3NH2 3NH- 
C)  C6H5NH2 3NH2 - 6H5CO2- 3NH- 
D)  CH3NH- 6H5CO2- - 3NH2 6H5NH2 
E)  none of the above

Question 13

When NH4Cl is added to a 0.10 M NH3 solution, the pH of this solution

Accepted Answer

A)  increases. 
B)  decreases. 
C)  remains the same. 
D)  increases at first and then decreases. 
E)  decreases at first and then increases. 
A)  increases. 
B)  decreases. 
C)  remains the same. 
D)  increases at first and then decreases. 
E)  decreases at first and then increases.

Question 14

What is the [HOAc]/[OAc-] ratio in an acetic acid/sodium acetate buffer at pH = 4.9? (HOAc: Ka = 1.8 x 10-5)

Accepted Answer

A)  0.31 
B)  0.70 
C)  1.4 
D)  2.4 
E)  4.9 
A)  0.31 
B)  0.70 
C)  1.4 
D)  2.4 
E)  4.9

Question 15

What can be correctly concluded from the fact that the following acid-base reaction proceeds to the right, as written?

NH2-(aq) + HSO4-(aq)   NH3(aq) + SO42-(aq)

Accepted Answer

A)  NH3 is a stronger base than NH2-. 
B)  NH3 is a stronger acid than HSO4-. 
C)  NH3 is a weaker acid than NH2-. 
D)  NH3 is a weaker base than HSO4-. 
E)  NH3 is a weaker acid than HSO4-. 
A)  NH3 is a stronger base than NH2-. 
B)  NH3 is a stronger acid than HSO4-. 
C)  NH3 is a weaker acid than NH2-. 
D)  NH3 is a weaker base than HSO4-. 
E)  NH3 is a weaker acid than HSO4-.

Question 16

Which of the following would be the strongest Brønsted base?

Accepted Answer

A)  H2O 
B)  SH- 
C)  OH- 
D)  S2- 
E)  O2- 
A)  H2O 
B)  SH- 
C)  OH- 
D)  S2- 
E)  O2-

Question 17

What is the H3O+ ion concentration in a solution that has a pH of 5.75?

Accepted Answer

A)  5.8 x 10-5 M 
B)  3.2 x 10-3 M 
C)  0.75 x 10-5 M 
D)  3.6 x 10-7 M 
E)  1.8 x 10-6 M 
A)  5.8 x 10-5 M 
B)  3.2 x 10-3 M 
C)  0.75 x 10-5 M 
D)  3.6 x 10-7 M 
E)  1.8 x 10-6 M

Question 18

Which of the following would be the weakest Brønsted acid?

Accepted Answer

A)  H2Se 
B)  H2S 
C)  H2O 
D)  SH- 
E)  OH- 
A)  H2Se 
B)  H2S 
C)  H2O 
D)  SH- 
E)  OH-

Question 19

A 0.10 M solution of a weak acid, HA, is found to be 1.50% ionized. Calculate Ka for this acid.

Accepted Answer

A)  1.5 
B)  2.3 x 10-1 
C)  2.3 x 10-5 
D)  2.3 x 10-6 
E)  none of the above 
A)  1.5 
B)  2.3 x 10-1 
C)  2.3 x 10-5 
D)  2.3 x 10-6 
E)  none of the above

Question 20

KHS can act as a weak acid or a weak base.
HS-(aq) + H2O(l)   S2-(aq) + H3O+(aq) &emsp; Ka2 = 1.3 x 10-13
HS-(aq) + H2O(l)   H2S(aq) + OH-(aq) &emsp; Kb2 = 1.0 x 10-7
Which of the following statements is correct?

Accepted Answer

A)  A solution of 0.1 M K2S and 0.1 M KHS will be acidic. 
B)  A solution of 0.01 M H2S will have a pH = 2. 
C)  A solution of 0.1 M KHS will be weakly basic. 
D)  H2S is over 90% ionized in water solution. 
E)  The S2- ion concentration in a 0.1 M KHS solution does not depend on pH. 
A)  A solution of 0.1 M K2S and 0.1 M KHS will be acidic. 
B)  A solution of 0.01 M H2S will have a pH = 2. 
C)  A solution of 0.1 M KHS will be weakly basic. 
D)  H2S is over 90% ionized in water solution. 
E)  The S2- ion concentration in a 0.1 M KHS solution does not depend on pH.

What is the [H₃O⁺] concentration of a solution with a pH of 8.75?

The dihydrogen phosphate ion, H₂PO₄ ^- , can behave as both an acid and as a base. What is the chemical formula of the conjugate acid of dihydrogen phosphate? What is the chemical formula of the conjugate base of dihydrogen phosphate?

A strong acid is added to water. Which of the following will be true?

What is the OH^- ion concentration in a 0.200 M NaOAc solution? (HOAc: K_a = 1.8 x 10^-5)

What is the K_b for methylamine (CH₃NH₂) if a 0.10 M solution of this weak base is 6.8% ionized?

What is the pH of a 0.10 M succinic acid, H₂Sc, solution if we assume that H₂Sc is a weak acid that undergoes stepwise dissociation? H₂Sc(aq) + H₂O(l) H₃O⁺(aq) + HSc^-(aq) K_a1 = 6.9 x 10^-5 HSc^-(aq) + H₂O(l) H₃O⁺(aq) + Sc^2-(aq) K_a2 = 2.5 x 10^-6

Which of the following is the conjugate base of a strong acid?

Which of the following statements should be true for a 1.0x 10 ^- ⁴ M solution of a strong acid HBr?

A solution is prepared by dissolving 1.0 x 10^-4 moles of HOBr in water and diluting to 1.00 L. What is the pH of this solution? (HOBr: K_a = 2 x 10^-9)

Using data from the previous problem, what fraction of the HSc^- formed in the first step of the dissociation of succinic acid goes on to dissociate to form Sc^2- ions in the second step, and what does this lead us to conclude?

Which of the following statements is true?

If the strength of the following acids increases from left to right CH₃NH₂ < CH₃NH₃⁺ < C₆H₅NH₃ ⁺ < C₆H₅CO₂H < HCl The order of increasing base strength, reading from left to right, must be:

When NH₄Cl is added to a 0.10 M NH₃ solution, the pH of this solution

What is the [HOAc]/[OAc^-] ratio in an acetic acid/sodium acetate buffer at pH = 4.9? (HOAc: K_a = 1.8 x 10^-5)

What can be correctly concluded from the fact that the following acid-base reaction proceeds to the right, as written? NH₂^-(aq) + HSO₄^-(aq) NH₃(aq) ⁺SO₄^2-(aq)

Which of the following would be the strongest Brønsted base?

What is the H₃O⁺ ion concentration in a solution that has a pH of 5.75?

Which of the following would be the weakest Brønsted acid?

A 0.10 M solution of a weak acid, HA, is found to be 1.50% ionized. Calculate K_a for this acid.

KHS can act as a weak acid or a weak base. HS^-(aq) + H₂O(l) S^2-(aq) + H₃O⁺(aq) K_a2 = 1.3 x 10^-13 HS^-(aq) + H₂O(l) H₂S(aq) + OH^-(aq) K_b2 = 1.0 x 10^-7 Which of the following statements is correct?

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Exam 11: Acids and Bases

What is the [H3O+] concentration of a solution with a pH of 8.75?

The dihydrogen phosphate ion, H2PO4 - , can behave as both an acid and as a base. What is the chemical formula of the conjugate acid of dihydrogen phosphate? What is the chemical formula of the conjugate base of dihydrogen phosphate?

A strong acid is added to water. Which of the following will be true?

What is the OH- ion concentration in a 0.200 M NaOAc solution? (HOAc: Ka = 1.8 x 10-5)

What is the Kb for methylamine (CH3NH2) if a 0.10 M solution of this weak base is 6.8% ionized?

What is the pH of a 0.10 M succinic acid, H2Sc, solution if we assume that H2Sc is a weak acid that undergoes stepwise dissociation? H2Sc(aq) + H2O(l) H3O+(aq) + HSc-(aq) Ka1 = 6.9 x 10-5 HSc-(aq) + H2O(l) H3O+(aq) + Sc2-(aq) Ka2 = 2.5 x 10-6

Which of the following is the conjugate base of a strong acid?

Which of the following statements should be true for a 1.0x 10 - 4 M solution of a strong acid HBr?

A solution is prepared by dissolving 1.0 x 10-4 moles of HOBr in water and diluting to 1.00 L. What is the pH of this solution? (HOBr: Ka = 2 x 10-9)

Using data from the previous problem, what fraction of the HSc- formed in the first step of the dissociation of succinic acid goes on to dissociate to form Sc2- ions in the second step, and what does this lead us to conclude?

Which of the following statements is true?

If the strength of the following acids increases from left to right CH3NH2 < CH3NH3+ < C6H5NH3 + < C6H5CO2H < HCl The order of increasing base strength, reading from left to right, must be:

When NH4Cl is added to a 0.10 M NH3 solution, the pH of this solution

What is the [HOAc]/[OAc-] ratio in an acetic acid/sodium acetate buffer at pH = 4.9? (HOAc: Ka = 1.8 x 10-5)

What can be correctly concluded from the fact that the following acid-base reaction proceeds to the right, as written? NH2-(aq) + HSO4-(aq) NH3(aq) + SO42-(aq)

Which of the following would be the strongest Brønsted base?

What is the H3O+ ion concentration in a solution that has a pH of 5.75?

Which of the following would be the weakest Brønsted acid?

A 0.10 M solution of a weak acid, HA, is found to be 1.50% ionized. Calculate Ka for this acid.

KHS can act as a weak acid or a weak base. HS-(aq) + H2O(l) S2-(aq) + H3O+(aq) Ka2 = 1.3 x 10-13 HS-(aq) + H2O(l) H2S(aq) + OH-(aq) Kb2 = 1.0 x 10-7 Which of the following statements is correct?

Elements Compounds

The Mole

Structure of the Atom

The Covalent Bond

Ionic and Metallic Bonds

Gases

Making and Breaking of Bonds

Liquids and Solutions

Solids

An Introduction to Kinetics and Equilibrium

Oxidation-Reduction Reactions

Chemical Thermodynamics

Kinetics

Nuclear Chemistry

Organic Chemistry

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What is the [H₃O⁺] concentration of a solution with a pH of 8.75?

The dihydrogen phosphate ion, H₂PO₄ ^- , can behave as both an acid and as a base. What is the chemical formula of the conjugate acid of dihydrogen phosphate? What is the chemical formula of the conjugate base of dihydrogen phosphate?

What is the OH^- ion concentration in a 0.200 M NaOAc solution? (HOAc: K_a = 1.8 x 10^-5)

What is the K_b for methylamine (CH₃NH₂) if a 0.10 M solution of this weak base is 6.8% ionized?

What is the pH of a 0.10 M succinic acid, H₂Sc, solution if we assume that H₂Sc is a weak acid that undergoes stepwise dissociation? H₂Sc(aq) + H₂O(l) H₃O⁺(aq) + HSc^-(aq) K_a1 = 6.9 x 10^-5 HSc^-(aq) + H₂O(l) H₃O⁺(aq) + Sc^2-(aq) K_a2 = 2.5 x 10^-6

Which of the following statements should be true for a 1.0x 10 ^- ⁴ M solution of a strong acid HBr?

A solution is prepared by dissolving 1.0 x 10^-4 moles of HOBr in water and diluting to 1.00 L. What is the pH of this solution? (HOBr: K_a = 2 x 10^-9)

Using data from the previous problem, what fraction of the HSc^- formed in the first step of the dissociation of succinic acid goes on to dissociate to form Sc^2- ions in the second step, and what does this lead us to conclude?

If the strength of the following acids increases from left to right CH₃NH₂ < CH₃NH₃⁺ < C₆H₅NH₃ ⁺ < C₆H₅CO₂H < HCl The order of increasing base strength, reading from left to right, must be:

When NH₄Cl is added to a 0.10 M NH₃ solution, the pH of this solution

What is the [HOAc]/[OAc^-] ratio in an acetic acid/sodium acetate buffer at pH = 4.9? (HOAc: K_a = 1.8 x 10^-5)

What can be correctly concluded from the fact that the following acid-base reaction proceeds to the right, as written? NH₂^-(aq) + HSO₄^-(aq) NH₃(aq) ⁺SO₄^2-(aq)

What is the H₃O⁺ ion concentration in a solution that has a pH of 5.75?

A 0.10 M solution of a weak acid, HA, is found to be 1.50% ionized. Calculate K_a for this acid.

KHS can act as a weak acid or a weak base. HS^-(aq) + H₂O(l) S^2-(aq) + H₃O⁺(aq) K_a2 = 1.3 x 10^-13 HS^-(aq) + H₂O(l) H₂S(aq) + OH^-(aq) K_b2 = 1.0 x 10^-7 Which of the following statements is correct?