Deck 16: Acid-Base Equilibria

Question 1

Of the following acids, __________ is a strong acid.

A)HNO₂
B)H₂CO₃
C)HBrO₃
D)HClO
E)HF

Answer 1

HBrO₃

Question 2

Of the following acids, __________ is not a strong acid.

A)HNO₂
B)H₂SO₄
C)HNO₃
D)HClO₄
E)HCl

Answer 2

HNO₂

Question 3

Of the following, __________ is a weak acid.

A)HF
B)HCl
C)HBr
D)HNO₃
E)HClO₄

Answer 3

HF

Question 4

Which one of the following statements regarding K_w is false?

A)pK_w is 14.00 at 25°C
B)The value of K_w is always 1.0 × 10^-14.
C)K_w changes with temperature.
D)The value of K_w shows that water is a weak acid.
E)K_w is known as the ion product of water.

Question 5

The magnitude of K_w indicates that __________.

A)water autoionizes very slowly
B)water autoionizes very quickly
C)water autoionizes only to a very small extent
D)the autoionization of water is exothermic

Question 6

A substance that is capable of acting as both an acid and as a base is __________.

A)autosomal
B)conjugated
C)amphoteric
D)saturated
E)miscible

Question 7

Which one of the following is a BrØnsted -Lowry base?

A)(CH₃)³N
B)CH₃COOH
C)HF
D)HNO₂
E)none of the above

Question 8

In basic solution, __________.

A)[H₃O⁺] = [OH^-]
B)[H₃O⁺] > [OH^-]
C)[H₃O⁺] < [OH^-]
D)[H₃O⁺] = 0 M
E)[OH^-] > 7.00

Question 9

The hydride ion, H^-, is a stronger base than the hydroxide ion, OH^-. The product(s)of the reaction of hydride ion with water is/ are __________.

A)H₃O⁺ (aq)
B)OH^- (aq)+ H₂ (g)
C)OH^- (aq)+ 2H⁺ (aq)
D)no reaction occurs
E)H₂O₂ (aq)

Question 10

A BrØnsted-Lowry acid is defined as a substance that __________.

A)increases K_a when placed in H₂O
B)decreases [H⁺] when placed in H₂O
C)increases [OH^-] when placed in H₂O
D)acts as a proton acceptor
E)acts as a proton donor

Question 11

According to the Arrhenius concept, an acid is a substance that __________.

A)is capable of donating one or more H⁺
B)causes an increase in the concentration of H⁺ in aqueous solutions
C)can accept a pair of electrons to form a coordinate covalent bond
D)reacts with the solvent to form the cation formed by autoionization of that solvent
E)tastes bitter

Question 12

The molar concentration of hydroxide ion in pure water at 25°C is __________.

A)1.00
B)0.00
C)1.0 ×10^-14
D)1.0 × 10^-7
E)7.00

Question 13

Which solution below has the highest concentration of hydronium ions?

A)pH = 3.21
B)pH = 12.6
C)pH = 7.93
D)pH = 9.82
E)pH = 7.00

Question 14

Which one of the following is the weakest acid?

A)HF (K_a = 6.8 × 10^-4)
B)HClO (K_a = 3.0 × 10^-8)
C)HNO₂ (K_a = 4.5 × 10^-4)
D)HCN (K_a = 4.9 × 10^-10)
E)Acetic acid (K_a = 1.8 × 10^-5)

Question 15

A BrØnsted-Lowry base is defined as a substance that __________.

A)increases [H⁺] when placed in H₂O
B)decreases [H⁺] when placed in H₂O
C)increases [OH^-] when placed in H₂O
D)acts as a proton acceptor
E)acts as a proton donor

Question 16

An aqueous solution contains 0.10 M NaOH. The solution is __________.

A)very dilute
B)highly colored
C)basic
D)neutral
E)acidic

Question 17

Nitric acid is a strong acid. This means that __________.

A)aqueous solutions of HNO₃ contain equal concentrations of H⁺(aq)and OH^-(aq)
B)HNO₃ does not dissociate at all when it is dissolved in water
C)HNO₃ dissociates completely to H⁺(aq)and NO₃^-(aq)when it dissolves in water
D)HNO₃ produces a gaseous product when it is neutralized
E)HNO₃ cannot be neutralized by a weak base

Question 18

The molar concentration of hydronium ion in pure water at 25°C is __________.

A)0.00
B)1.0 × 10^-7
C)1.0 × 10^-14
D)1.00
E)7.00

Question 19

Which one of the following is a BrØnsted -Lowry acid?

A)(CH₃)³NH⁺
B)CH₃COOH
C)HF
D)HNO₂
E)all of the above

Question 20

Which solution below has the highest concentration of hydroxide ions?

A)pH = 3.21
B)pH = 12.6
C)pH = 7.93
D)pH = 9.82
E)pH = 7.00

Question 21

A- is a weak base. Which equilibrium corresponds to the equilibrium constant K_a for HA?

A)HA (aq)+ H₂O (l) H₂A⁺ (aq)+ OH^- (aq)
B)A^- (aq)+ H₃O⁺ (aq) HA (aq)+ H₂O (l)
C)HA (aq)+ H₂O (l) H₃O⁺ (aq)+ A^- (aq)
D)A^- (aq)+ H₂O (l) HA (aq)+ OH^- (aq)
E)A^- (aq)+ OH^- (aq) HOA^2- (aq)

Question 22

HA is a weak acid. Which equilibrium corresponds to the equilibrium constant K_b for A^-?

A)HA (aq)+ H₂O (l) H₂A⁺ (aq)+ OH^- (aq)
B)A^- (aq)+ H₃O⁺ (aq) HA (aq)+ H₂O (l)
C)HA (aq)+ OH^- (aq) H₂O (l)+ H⁺ (aq)
D)A^- (aq)+ H₂O (l) HA (aq)+ OH^- (aq)
E)A^- (aq)+ OH^- (aq) HOA^2- (aq)

Question 23

Ammonia is a __________.

A)weak acid
B)strong base
C)weak base
D)strong acid
E)salt

Question 24

Classify the following compounds as weak bases (W)or strong bases (S): ammonia fluoride ion sodium hydroxide

A)W W S
B)S S S
C)S W W
D)W S S
E)W S W

Question 25

Using the data in the table, which of the conjugate acids below is the strongest acid?

A)HClO
B)HCO₃^-
C)H₂S
D)NH₃CH₃⁺
E)H₂S and HClO

Question 26

Classify the following compounds as weak acids (W)or strong acids (S): benzoic acid nitric acid acetic acid

A)W W W
B)S S S
C)S W W
D)W S S
E)W S W

Question 27

Classify the following compounds as weak acids (W)or strong acids (S): hypochlorous acid perchloric acid chloric acid

A)W S S
B)S S S
C)S W W
D)W W W
E)W S W

Question 28

Using the data in the table, which of the conjugate bases below is the weakest base?

A)OAc^-
B)C₇H₅O₂-
C)NO₂^-
D)F^-
E)OAc^- and C₇H₅O₂-

Question 29

In which of the following aqueous solutions does the weak acid exhibit the highest percentage ionization?

A)0.01 M HC₂H₃O₂ (K_a = 1.8 × 10^-5)
B)0.01 M HNO₂ (K_a = 4.5 × 10^-4)
C)0.01 M HF (K_a = 6.8 × 10^-4)
D)0.01 M HClO (K_a = 3.0 × 10^-8)
E)These will all exhibit the same percentage ionization.

Question 30

Using the data in the table, which of the conjugate acids below is the weakest acid?

A)HClO
B)HCO₃^-
C)H₂S
D)NH₃CH₃⁺
E)H₂S and HClO

Question 31

Of the acids in the table below, __________ is the strongest acid.

A)HOAc
B)HCHO₂
C)HClO
D)HF
E)HOAc and HCHO₂

Question 32

Using the data in the table, which of the conjugate acids below is the strongest acid?

A)NH₄⁺
B)C₅H₅NH⁺
C)H₃NOH⁺
D)NH₃CH₃⁺
E)NH₄⁺ and NH₃CH3⁺

Question 33

In which of the following aqueous solutions does the weak acid exhibit the lowest percentage ionization?

A)0.01 M HC₂H₃O₂ (K_a = 1.8 × 10^-5)
B)0.01 M HNO₂ (K_a = 4.5 × 10^-4)
C)0.01 M HF (K_a = 6.8 × 10^-4)
D)0.01 M HClO (K_a = 3.0 × 10^-8)
E)These will all exhibit the same percentage ionization.

Question 34

The K_a of hypochlorous acid (HClO)is 3.0 × 10^-8 at 25.0°C. What is the % ionization of hypochlorous acid in a 0.015 M aqueous solution of HClO at 25.0°C?

A)4.5 × 10^-8
B)14
C)2.1 × 10^-5
D)0.14
E)1.4 × 10^-3

Question 35

Classify the following compounds as weak bases (W)or strong bases (S): methylamine carbonate ion potassium hydroxide

A)W W S
B)S S S
C)S W W
D)W S S
E)W S W

Question 36

Using the data in the table, which of the conjugate bases below is the strongest base?

A)OAc^-
B)CHO₂^-
C)ClO^-
D)F^-
E)OAc^- and CHO₂^-

Question 37

Using the data in the table, which of the conjugate bases below is the weakest base?

A)OAc^-
B)CHO₂^-
C)ClO^-
D)F^-
E)OAc^- and CHO₂^-

Question 38

Classify the following compounds as weak acids (W)or strong acids (S): hydrocyanic acid hydrofluoric acid phenol

A)W W W
B)S S S
C)S W W
D)W S S
E)W S W

Question 39

Classify the following compounds as weak acids (W)or strong acids (S): nitrous acid hydrochloric acid hydrofluoric acid

A)W W W
B)S S S
C)S W W
D)W S S
E)W S W

Question 40

Using the data in the table, which of the conjugate bases below is the strongest base?

A)OAc^-
B)C₇H₅O₂-
C)NO₂^-
D)F^-
E)OAc^- and C₇H₅O₂-

Question 41

Which of the following ions will act as a weak base in water?

A)HS^-
B)F^-
C)NO₂^-
D)ClO^-
E)All of the above will act as a weak base in water.

Question 42

Of the following, which is the strongest acid?

A)HIO
B)HIO₄
C)HIO₂
D)HIO₃
E)The acid strength of all of the above is the same.

Question 43

Which of the following aqueous solutions has the lowest [OH^-]?

A)a solution with a pH of 3.0
B)a 1 × 10^-4 M solution of HNO₃
C)a solution with a pOH of 12.0
D)pure water
E)a 1 × 10^-3 M solution of NH₄Cl

Question 44

Of the following, which is the strongest acid?

A)HClO
B)HClO₃
C)HClO₂
D)HClO₄
E)HIO

Question 45

A 0.1 M aqueous solution of __________ will have a pH of 7.0 at 25.0°C. NaOCl KCl NH₄Cl Ca(OAc)₂

A)NaOCl
B)KCl
C)NH₄Cl
D)Ca(OAc)₂
E)KCl and NH₄Cl

Question 46

The conjugate base of HSO₄^- is __________.

A)OH^-
B)H₂SO₄
C)SO₄^2-
D)HSO₄⁺
E)H₃SO₄⁺

Question 47

Of the compounds below, a 0.1 M aqueous solution of __________ will have the highest pH.

A)KCN, K_a of HCN = 4.0 × 10^-10
B)NH₄NO₃, K_b of NH₃ = 1.8 × 10^-5
C)NaOAc, K_a of HOAc = 1.8 × 10^-5
D)NaClO, K_a of HClO = 3.2 × 10^-8
E)NaHS, K_b of HS^- = 1.8 × 10^-7

Question 48

A 0.1 M solution of __________ has a pH of 7.0.

A)Na₂S
B)KF
C)NaNO₃
D)NH₄Cl
E)NaF

Question 49

In the gas phase reaction below, NH₃ is acting as a(n)__________ base but not as a(n)__________ base. H⁺
. . |
N + H⁺ → N
| |
H H H H H H

A)Arrhenius, BrØnsted-Lowry
B)BrØnsted-Lowry, Lewis
C)Lewis, Arrhenius
D)Lewis, BrØnsted-Lowry
E)Arrhenius, Lewis

Question 50

Using the data in the table, which of the conjugate acids below is the weakest acid?

A)NH₄⁺
B)C₅H₅NH⁺
C)H₃NOH⁺
D)NH₃CH₃⁺
E)NH₄⁺ and NH₃CH3⁺

Question 51

A 0.0035 M aqueous solution of a particular compound has pH = 2.46. The compound is __________.

A)a weak base
B)a weak acid
C)a strong acid
D)a strong base
E)a salt

Question 52

Of the following substances, an aqueous solution of __________ will form basic solutions. NH₄Cl Cu(NO₃)₂ K₂CO₃ NaF

A)NH₄Cl, Cu(NO₃)₂
B)K₂CO₃, NH₄Cl
C)NaF only
D)NaF, K₂CO₃
E)NH₄Cl only

Question 53

What is the conjugate acid of CO₃^-2?

A)CO₂^-2
B)HCO₂^-2
C)H₂CO₃
D)HCO₃^-
E)none of the above

Question 54

Which of the following aqueous solutions has the highest [OH^-]?

A)a solution with a pH of 3.0
B)a 1 × 10^-4 M solution of HNO₃
C)a solution with a pOH of 12.0
D)pure water
E)a 1 × 10^-3 M solution of NH₄Cl

Question 55

What is the conjugate acid of NH₃?

A)NH₃
B)NH₂⁺
C)NH₃⁺
D)NH₄⁺
E)NH₄OH

Question 56

Of the following, which is the weakest acid?

A)HIO
B)HIO₄
C)HIO₂
D)HIO₃
E)The acid strength of all of the above is the same.

Question 57

Which of the following acids will be the strongest?

A)H₂SO₄
B)HSO₄^-
C)H₂SO₃
D)H₂SeO₄
E)HSO₃^-

Question 58

Which of the following ions will act as a weak base in water?

A)OH^-
B)Cl^-
C)NO₃^-
D)ClO^-
E)None of the above will act as a weak base in water.

Question 59

An aqueous solution of __________ will produce a basic solution.

A)NH₄ClO₄
B)KBr
C)NaCl
D)NaHSO₄
E)Na₂SO₃

Question 60

Of the following substances, an aqueous solution of __________ will form basic solutions. NaHS Cu(NO₃)₂ KHCO₃ NaF

A)NaHS, Cu(NO₃)₂
B)KHCO₃, NaHS
C)NaF only
D)NaF, KHCO₃
E)NaHS, KHCO₃ and NaF

Question 61

What is the pOH of an aqueous solution at 25.0 °C that contains 3.98 × 10^-9 M hydroxide ion?

A)8.40
B)5.60
C)9.00
D)3.98
E)7.00

Question 62

The conjugate acid of CH₃NH₂ is __________.

A)CH₃NH₂
B)CH₃NH₃⁺
C)CH3NH₃⁺
D)CH₃NH⁺
E)none of the above

Question 63

A 0.15 M aqueous solution of the weak acid HA at 25.0°C has a pH of 5.35. The value of K_a for HA is __________.

A)3.0 × 10^-5
B)1.8 × 10^-5
C)7.1 × 10^-9
D)1.3 × 10^-10
E)3.3 × 10⁴

Question 64

HZ is a weak acid. An aqueous solution of HZ is prepared by dissolving 0.020 mol of HZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 4.93 at 25.0°C. The K_a of HZ is __________.

A)1.2 × 10^-5
B)6.9 × 10^-9
C)1.4 × 10^-10
D)9.9 × 10^-2
E)2.8 × 10^-12

Question 65

The pH of a 0.60 M aqueous solution of formic acid, HCHO₂, at 25.0°C is 1.98. What is the value of K_a for formic acid?

A)2.0 × 10^-5
B)1.8 × 10^-4
C)6.0 × 10^-5
D)3.5 × 10^-4
E)none of the above

Question 66

Calculate the pH of a solution at 25.0 °C that contains 1.94 × 10^-10 M hydronium ions.

A)1.94
B)4.29
C)7.00
D)14.0
E)9.71

Question 67

What is the pH of an aqueous solution at 25.0 °C that contains 3.98 × 10^-9 M hydronium ion?

A)8.400
B)5.600
C)9.000
D)3.980
E)7.000

Question 68

The conjugate acid of HSO₄^- is __________.

A)SO₄^2-
B)H₂SO₄
C)HSO₄⁺
D)H⁺
E)HSO₃⁺

Question 69

What is the pH of an aqueous solution at 25.0 °C that contains 3.98 × 10^-9 M hydroxide ion?

A)8.40
B)5.60
C)9.00
D)3.98
E)7.00

Question 70

An aqueous solution contains 0.150 M HCl at 25.0°C. The pH of the solution is __________.

A)0.150
B)1.00
C)13.00
D)7.00
E)0.82

Question 71

The pH of a 0.55 M aqueous solution of hypobromous acid, HBrO, at 25.0°C is 4.48. What is the value of K_a for HBrO?

A)2.0 × 10^-9
B)1.1 × 10^-9
C)6.0 × 10^-5
D)3.3 × 10^-5
E)3.0 × 10⁴

Question 72

The K_a of hypochlorous acid (HClO)is 3.00 × 10^-8. What is the pH at 25.0°C of an aqueous solution that is 0.0200 M in HClO?

A)+2.45
B)-2.45
C)-9.22
D)+9.22
E)+4.61

Question 73

What is the pOH of an aqueous solution at 25.0 °C that contains 3.98 × 10^-9 M hydronium ion?

A)8.400
B)5.600
C)9.000
D)3.980
E)7.000

Question 74

What is the conjugate base of OH^-?

A)O₂
B)O^-
C)H₂O
D)O^2-
E)H₃O⁺

Question 75

An aqueous solution contains 0.100 M NaOH at 25.0°C. The pH of the solution is __________.

A)0.100
B)1.00
C)13.00
D)7.00
E)-1.00

Question 76

The pH of a 0.25 M aqueous solution of hydrofluoric acid, HF, at 25.0°C is 2.03. What is the value of K_a for HF?

A)2.0 × 10^-9
B)1.1 × 10^-9
C)6.0 × 10^-5
D)3.5 × 10^-4
E)none of the above

Question 77

The conjugate base of H₂PO₄^- is __________.

A)PO₄^-3
B)H₂PO₄
C)H₃PO₄
D)HPO₄^-2
E)none of the above

Question 78

Calculate the concentration (in M)of hydroxide ions in a solution at 25.0°C with a pOH of 4.223.

A)5.98 × 10^-5
B)1.67 × 10^-10
C)1.67 × 10⁴
D)5.99 × 10^-19
E)1.00 × 10^-7

Question 79

Calculate the concentration (in M)of hydronium ions in a solution at 25.0°C with a pOH of 4.223.

A)5.98 × 10^-5
B)1.67 × 10^-10
C)1.67 × 10⁴
D)5.99 × 10^-19
E)1.00 × 10^-7

Question 80

Calculate the pOH of a solution at 25.0 °C that contains 1.94 × 10^-10 M hydronium ions.

A)1.94
B)4.29
C)7.00
D)14.0
E)9.71