Question 1

The ammonium ion, NH4+, is a weak acid.

Accepted Answer

A) True 
 B)False

Question 2

What is the pH of a 0.20 M HCl solution?

Accepted Answer

A)   
B)   0.70
C)   1.61
D)   12.39
E)   13.30

Question 3

Lactic acid has a pKa of 3.08. What is the approximate degree of dissociation of a 0.35 M solution of lactic acid?

Accepted Answer

A)   1.1%
B)   2.2%
C)   4.8%
D)   14%
E)   None of these choices is correct.

Question 4

A 1.25 M solution of the weak acid HA is 9.2% dissociated. What is the pH of the solution?

Accepted Answer

A)   0.64
B)   0.94
C)   1.13
D)   2.16
E)   None of these choices is correct.

Question 5

Which one of the following is a strong acid?

Accepted Answer

A)   H2CO3
B)   H2SO3
C)   H2SO4
D)   H3PO4
E)   CH3COOH

Question 6

In order to be a Brønsted-Lowry base, a species must contain a proton.

Accepted Answer

A) True 
 B)False

Question 7

Select the pair of substances which is not a conjugate acid-base pair.

Accepted Answer

A)   H3O+, H2O
B)   HNO2, NO2¯
C)   H2SO4, HSO4¯
D)   H2S, S2¯
E)   NH3, NH2¯

Question 8

What is the value of Ka for the methylammonium ion, CH3NH3+? Kb(CH3NH2)  = 4.4 *10¯4

Accepted Answer

A)   4.4 * 10¯4
B)   4.8 * 10¯6
C)   4.4 * 10¯10
D)   2.3 * 10¯11
E)   4.4 * 10¯18

Question 9

What is the value of Kb for the cyanide anion, CN¯? Ka(HCN)  = 6.2 * 10¯10

Accepted Answer

A)   1.6 * 10¯4
B)   1.6 * 10¯5
C)   3.8 *10¯4
D)   3.8 * 10¯5
E)   6.2 * 104

Question 10

The substance Ca(OH) 2 is considered

Accepted Answer

A)   a weak Arrhenius acid.
B)   a weak Arrhenius base.
C)   a strong Arrhenius acid.
D)   a strong Arrhenius base.
E)   a neutral compound.

Question 11

Aqueous solutions of phosphoric acid and sodium nitrite are combined, and the following equilibrium is established. c for this reaction is greater than one. Based on this information, which of the following statements is correct? A)  Phosphoric acid is a weaker acid than nitrous acid. B)  Nitrous acid is a weaker acid than water. C)  The nitrite anion is a weaker base than the dihydrogen phosphate anion. D)  The dihydrogen phosphate anion is a stronger acid than nitrous acid. E)  Phosphoric acid is a stronger acid than nitrous acid." class="answers-bank-image d-inline" rel="preload" > The equilibrium constant Kc for this reaction is greater than one. Based on this information, which of the following statements is correct?

Accepted Answer

A)   Phosphoric acid is a weaker acid than nitrous acid.
B)   Nitrous acid is a weaker acid than water.
C)   The nitrite anion is a weaker base than the dihydrogen phosphate anion.
D)   The dihydrogen phosphate anion is a stronger acid than nitrous acid.
E)   Phosphoric acid is a stronger acid than nitrous acid.

Question 12

What is the pH of a 0.050 M HBr solution?

Accepted Answer

A)   0.89
B)   1.12
C)   1.30
D)   3.00
E)   None of these choices is correct.

Question 13

Which one of the following substances will give an aqueous solution of pH closest to 7?

Accepted Answer

A)   KNO3
B)   CO2
C)   NH4I
D)   NH3
E)   CH3NH2

Question 14

A solution is prepared by adding 0.10 mol of potassium chloride, KCl, to 1.00 L of water. Which statement about the solution is correct?

Accepted Answer

A)   The solution is basic.
B)   The solution is neutral.
C)   The solution is acidic.
D)   One needs to know the temperature before any of the above predictions can be made.
E)   The values for Ka and Kb for the species in solution must be known before a prediction can be made.

Question 15

All Lewis acids contain at least one proton.

Accepted Answer

A) True 
 B)False

Question 16

The chloride ion, Cl¯, is a typical Lewis acid.

Accepted Answer

A) True 
 B)False

Question 17

An aqueous solution is prepared by dissolving the salt formed by the neutralization of a weak acid by a weak base. Which statement about the solution is correct?

Accepted Answer

A)   The solution is strongly basic.
B)   The solution is weakly basic.
C)   The solution is neutral.
D)   The solution is acidic.
E)   The values for Ka and Kb for the species in solution must be known before a prediction can be made.

Question 18

Which of the following is the strongest base?

Accepted Answer

A)   CH3NH2
B)   NaNO3
C)   B(OH) 3
D)   Al(OH) 3
E)   LiOH

Question 19

The substance HOBr is considered

Accepted Answer

A)   a weak Arrhenius acid.
B)   a weak Arrhenius base.
C)   a strong Arrhenius acid.
D)   a strong Arrhenius base.
E)   a neutral compound.

Question 20

Which of the following aqueous liquids is the most acidic?

Accepted Answer

A)   0.1 M Al(NO3) 3, Ka = 1 *10¯5
B)   0.1 M Be(NO3) 2, Ka = 4 *10¯6
C)   0.1 M Pb(NO3) 2, Ka = 3 *10¯8
D)   0.1 M Ni(NO3) 2, Ka = 1 * 10¯10
E)   pure water

Exam 18: Acid-Base Equilibria

Select the pair of substances which is not a conjugate acid-base pair.

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All Lewis acids contain at least one proton.

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What is the value of Ka for the methylammonium ion, CH3NH3+? Kb(CH3NH2) = 4.4 *10¯4

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What is the pH of a 0.20 M HCl solution?

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The substance Ca(OH) 2 is considered

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A 1.25 M solution of the weak acid HA is 9.2% dissociated. What is the pH of the solution?

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The ammonium ion, NH4+, is a weak acid.

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Which of the following aqueous liquids is the most acidic?

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A solution is prepared by adding 0.10 mol of potassium chloride, KCl, to 1.00 L of water. Which statement about the solution is correct?

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What is the pH of a 0.050 M HBr solution?

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In order to be a Brønsted-Lowry base, a species must contain a proton.

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The chloride ion, Cl¯, is a typical Lewis acid.

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What is the value of Kb for the cyanide anion, CN¯? Ka(HCN) = 6.2 * 10¯10

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An aqueous solution is prepared by dissolving the salt formed by the neutralization of a weak acid by a weak base. Which statement about the solution is correct?

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Aqueous solutions of phosphoric acid and sodium nitrite are combined, and the following equilibrium is established. The equilibrium constant Kc for this reaction is greater than one. Based on this information, which of the following statements is correct?

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Which one of the following is a strong acid?

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Lactic acid has a pKa of 3.08. What is the approximate degree of dissociation of a 0.35 M solution of lactic acid?

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Which of the following is the strongest base?

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The substance HOBr is considered

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Which one of the following substances will give an aqueous solution of pH closest to 7?

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What is the value of K_a for the methylammonium ion, CH₃NH₃⁺? K_b(CH₃NH₂) = 4.4 *10¯⁴

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The substance Ca(OH) ₂ is considered

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The ammonium ion, NH₄⁺, is a weak acid.

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What is the value of K_b for the cyanide anion, CN¯? K_a(HCN) = 6.2 * 10¯¹⁰

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Aqueous solutions of phosphoric acid and sodium nitrite are combined, and the following equilibrium is established. The equilibrium constant K_c for this reaction is greater than one. Based on this information, which of the following statements is correct?

Correct Answer
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Lactic acid has a pK_a of 3.08. What is the approximate degree of dissociation of a 0.35 M solution of lactic acid?

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