Deck 15: Aqueous Equilibria: Acids and Bases

Question 1

Identify the conjugate acid/base pairs present in an aqueous solution of hydrogen sulfate ion,HSO₄^-.

A)HSO₄^-/SO₄^2- and H₃O⁺/H₂O
B)H₂SO₄/HSO₄^- and H₂O/OH^-
C)HSO₄^-/H₂O and H₃O⁺/SO₄^2-
D)HSO₄^-/H₂O and H₂SO₄/OH^-

Answer 1

HSO₄^-/SO₄^2- and H₃O⁺/H₂O

Question 2

Using the conjugate acid-base pairs listed below,complete the following equation with the pair that gives an equilibrium constant K_c > 1. ________ + H₂CO₃ ⇌ ________ + HCO₃^-

A)HF/F^-
B)HCl/Cl^-
C)HOCl/OCl^-
D)HSO₄^2-/SO₄^2-

Answer 2

HOCl/OCl^-

Question 3

From the following chemical reactions determine the relative Br∅nsted-Lowry base strengths (strongest to weakest). HNO₃(aq)+ H₂O(l)→ H₃O⁺(aq)+ NO₃^-(aq)
HF(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ F^-(aq)

A)HNO₃ > H₃O⁺ > HF
B)NO₃^- > H₂O > F^-
C)F^- > H₂O > NO₃^-
D)F^- > NO₃^- > H₂O

Answer 3

F^- > H₂O > NO₃^-

Question 4

Which of the following Br∅nsted-Lowry acids does not behave as a strong acid when it is dissolved in water?

A)HBr
B)HCl
C)HNO₂
D)HClO₄

Question 5

When dissolved in water,which of the following compounds is an Arrhenius acid?

A)HCN
B)NaOH
C)NaF
D)CH₃CH₂OH

Question 6

What are the Br∅nsted-Lowry bases in the following chemical reaction? C₅H₅N(aq)+ H₂O(l)⇌ C₅H₅NH+(aq)+ OH-(aq)

A)C₅H₅N,H₂O
B)C₅H₅N,C₅H₅NH⁺
C)C₅H₅N,OH^-
D)C₅H₅N,H₂O,OH^-

Question 7

From the following chemical reactions determine the relative Br∅nsted-Lowry acid strengths (strongest to weakest). HClO₄(sol)+ CH₃COOH(l)→ CH₃C₂(OH)₂⁺(sol)+ ClO₄^-(aq)
H₂SO₄(sol)+ CH₃COOH(l)⇌ CH₃C(OH)₂⁺(sol)+ HSO₄^-(sol)

A)HClO₄ > H₂SO₄ > CH₃COOH
B)HClO₄ > H₂SO₄ > CH₃C(OH)₂⁺
C)HClO₄ > CH₃COOH > H₂SO₄
D)HClO₄ > CH₃C(OH)₂⁺ > H₂SO₄

Question 8

What are the Br∅nsted-Lowry acids in the following chemical reaction? HBr(sol)+ CH₃COOH(sol)⇌ CH₃C(OH)₂⁺(sol)+ Br^-(sol)

A)HBr,CH₃COOH
B)HBr,CH₃C(OH)₂⁺
C)CH₃COOH,CH₃C(OH)₂⁺
D)CH₃COOH,Br^-

Question 9

From the following chemical reactions determine the relative Br∅nsted-Lowry acid strengths (strongest to weakest). HClO₄(aq)+ H₂O(l)→ H₃O⁺(aq)+ ClO₄^-(aq)
HNO₂(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ NO₂^-(aq)

A)HClO₄ > H₃O⁺ > HNO₂
B)HClO₄ > HNO₂ > H₃O⁺
C)H₃O⁺ > HClO₄ > HNO₂
D)H₃O⁺ > HNO₂ > HClO₄

Question 10

Arrange the acids in order of increasing acid strength.

A)D < C < A < B
B)D < C < B < A
C)D < B < A < C
D)D < A < C < B

Question 11

What is the conjugate acid of the Br∅nsted-Lowry base HAsO₄^2-?

A)H₂AsO₄^-
B)AsO₄^3-
C)H₂O
D)H₃O⁺

Question 12

Write a balanced equation for the dissociation of the Br∅nsted-Lowry acid HSO₄^- in water.

A)HSO₄^-(aq)+ H₂O(l)⇌ H₂SO₄(aq)+ OH^-(aq)
B)HSO₄^-(aq)+ H₂O(l)⇌ SO₄^2-(aq)+ H₃O⁺(aq)
C)HSO₄^-(aq)+ H₂O(l)⇌ SO₃^2-(aq)+ OH^-(aq)
D)HSO₄^-(aq)+ H₂O(l)⇌ SO₃(g)+ OH^-(aq)+ H₂O(l)

Question 13

From the following chemical reactions determine the relative Br∅nsted-Lowry base strengths (strongest to weakest). 2 NaH(s)+ H₂O(l)→ 2 NaOH + H₂(g)
NH₃(aq)+ H₂O(l)⇌ NH₄⁺(aq)+ OH^-(aq)

A)H^- > OH^- > NH₃
B)H^- > NH₃ > OH^-
C)OH^-> H^- > NH₃
D)OH^- > NH₃ > H^-

Question 14

From the following chemical reactions determine the relative Br∅nsted-Lowry acid strengths (strongest to weakest). HCl(aq)+ H₂O(l)→ H₃O⁺(aq)+ Cl^-(aq)
HCN(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ CN^-(aq)

A)HCl > HCN > H₃O⁺
B)HCl > H₃O⁺ > HCN
C)H₃O⁺ > HCl > HCN
D)HCN > H₃O⁺ > HCl

Question 15

What is the conjugate base of the Br∅nsted-Lowry acid HPO₄^2-?

A)H₃PO₄
B)H₂PO₄^-
C)HPO₄^2-
D)PO₄^3-

Question 16

The following pictures represent aqueous solutions of binary acids of the type HA where the water molecules have been omitted for clarity.
Determine the strongest acid of the set.

A)A
B)B
C)C
D)D

Question 17

What are the conjugate acid-base pairs in the following chemical reaction? NH₃(aq)+ H₂O(l)⇌ NH₄⁺(aq)+ OH^-(aq)

A)NH₃,H₂O and NH₄⁺,OH^-
B)NH₃,NH₄⁺ and H₂O,OH^-
C)NH₃,OH^- and H₂O,NH₄⁺
D)NH₃ and NH₄⁺

Question 18

What is the strongest Br∅nsted-Lowry acid in the chemical reaction shown below? 2 HNO₃(aq)+ Ba(OH)₂(aq)→ Ba(NO₃)₂(aq)+ 2 H₂O(l)

A)HNO₃
B)Ba(OH)₂
C)Ba(NO₃)₂
D)H₂O

Question 19

The equilibrium constant,K,for the reaction shown below has a value 1.8 × 10^-5.In this reaction which is the strongest acid and which is the strongest base? CH₃CO₂H(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ CH₃CO₂^-(aq)

A)CH₃CO₂H and CH₃CO₂^-
B)CH₃CO₂H and H₂O
C)H₃O⁺ and H₂O
D)H₃O⁺ and CH₃CO₂^-

Question 20

Using the conjugate acid-base pairs listed below,complete the following equation with the pair that gives an equilibrium constant K_c > 1. ________ + HSO₃^- ⇌ ________ + H₂SO₃

A)CH₃CO₂H/ CH₃CO₂^-
B)HCO₂H/ HCO₂^-
C)HNO₂/NO₂^-
D)HNO₃/NO₃^-

Question 21

What is the strongest acid of the following?

A)HOI
B)HOBr
C)HOCl
D)All are equivalent.

Question 22

Calculate the pH for an aqueous solution of pyridine that contains 2.15 × 10^-4 M hydroxide ion.

A)4.65 × 10^-11
B)2.15 × 10^-4
C)3.67
D)10.33

Question 23

An acidic solution at 25°C has

A)[H₃O⁺] > [OH^-] > 1 × 10^-7 M.
B)[H₃O⁺] > 1 × 10^-7 M > [OH^-].
C)[H₃O⁺] = [OH^-] > 1 × 10^-7 M.
D)[H₃O⁺] < 1 × 10^-7 M > [OH^-].

Question 24

What is the weakest acid among the following?

A)SiH₄
B)PH₃
C)H₂S
D)HCl

Question 25

What is the hydronium ion concentration of an acid rain sample that has a pH of 3.15?

A)1.41 × 10^-11 M
B)7.08 × 10^-4 M
C)3.15 M
D)10.85 M

Question 26

Calculate the pH for an aqueous solution of acetic acid that contains 2.15 × 10^-3 M hydronium ion.

A)4.65 × 10^-12
B)2.15 × 10^-3
C)2.67
D)11.33

Question 27

If the ionization constant of water,K_w,at 40°C is 2.92 × 10^-14,then what is the hydronium ion concentration and pH for an acidic solution?

A)[H₃O⁺] > 1.71 × 10^-7 M and pH > 6.77
B)[H₃O⁺] > 1.71 × 10^-7 M and pH < 6.77
C)[H₃O⁺] < 1.71 × 10^-7 M and pH > 6.77
D)[H₃O⁺] < 1.71 × 10^-7 M and pH < 6.77

Question 28

What is the strongest acid among the following?

A)H₂O
B)H₂S
C)H₂Se
D)H₂Te

Question 29

If the ionization constant of water,K_w,at 40°C is 2.92 × 10^-14,then what is the hydronium ion concentration for a neutral solution?

A)[H₃O⁺] < 1.00 × 10^-7 M
B)[H₃O⁺] > 1.71 × 10^-7 M
C)[H₃O⁺] = 1.71 × 10^-7 M
D)[H₃O⁺] < 1.71 × 10^-7 M

Question 30

Human tears have a concentration of H₃O⁺ that is 3.16 × 10^-8.The concentration of OH^- in human tears is

A)greater than 3.16 × 10^-7 and tears are acidic.
B)greater than 3.16 ×10^-7 and tears are basic.
C)less than 3.16 × 10^-7 and tears are acidic.
D)less than 3.16 × 10^-7 and tears are basic.

Question 31

Calculate the hydroxide ion concentration in an aqueous solution that contains 3.50 × 10^-3 M in hydronium ion.

A)2.86 × 10^-4 M
B)2.86 × 10^-11 M
C)2.86 × 10^-12 M
D)3.50 × 10^-12 M

Question 32

A solution with a hydrogen ion concentration of 3.25 × 10^-2 M is ________ and has a hydroxide concentration of ________.

A)acidic,3.08 × 10^-12 M
B)acidic,3.08 × 10^-13 M
C)basic,3.08 × 10^-12 M
D)basic,3.08 × 10^-13 M

Question 33

Calculate the hydronium ion concentration in an aqueous solution that contains 2.50 × 10^-4 M in hydroxide ion.

A)4.00 × 10^-9 M
B)4.00 × 10^-10 M
C)4.00 × 10^-11 M
D)5.00 × 10^-11 M

Question 34

What is the strongest acid among the following?

A)HF
B)HCl
C)HBr
D)HI

Question 35

At 50°C the value of K_w is 5.5 × 10^-14.A basic solution at 50°C has

A)[H₃O⁺] < [OH^-] < 2 × 10^-7 M.
B)[H₃O⁺] < 2 × 10^-7 M < [OH^-].
C)[H₃O⁺] = [OH^-] < 2 × 10^-7 M.
D)[H₃O⁺] > 2 × 10^-7 M < [OH^-].

Question 36

What is the hydronium ion concentration and the pH for an aqueous solution of NH₃ that has a hydroxide ion concentration of 2.25 × 10^-3 M?

A)4.44 × 10^-11 M,3.65
B)4.44 × 10^-11 M,10.35
C)4.44 × 10^-12 M,2.65
D)4.44 × 10^-12 M,11.35

Question 37

Which of the following should have the lowest bond strength?

A)HOI
B)HOCl
C)HOAt
D)HOBr

Question 38

An acidic solution at 25°C will have a hydronium ion concentration ________ and a pH value ________.

A)[H₃O⁺] > 1 × 10^-7 M,pH > 7.00
B)[H₃O⁺] > 1 × 10^-7 M,pH < 7.00
C)[H₃O⁺] < 1 × 10^-7 M,pH > 7.00
D)[H₃O⁺] < 1 × 10^-7 M,pH < 7.00

Question 39

A solution with a hydroxide ion concentration of 4.15 × 10^-4 M is ________ and has a hydrogen ion concentration of ________.

A)acidic,2.41 × 10^-10 M
B)acidic,2.41 × 10^-11 M
C)basic,2.41 × 10^-10 M
D)basic,2.41 × 10^-11 M

Question 40

What is the hydroxide ion concentration and the pH for a hydrochloric acid solution that has a hydronium ion concentration of 1.50 × 10^-4 M?

A)6.67 × 10^-10 M,4.82
B)6.67 × 10^-10 M,9.18
C)6.67 × 10^-11 M,3.82
D)6.67 × 10^-11 M,10.18

Question 41

What is the pH of a solution made by mixing 100.0 mL of 0.10 M HNO₃,50.0 mL of 0.20 M HCl,and 100.0 mL of water? Assume that the volumes are additive.

A)0.30
B)0.82
C)1.00
D)1.10

Question 42

What is the pH of a solution prepared by diluting 25.00 mL of 0.020 M Ba(OH)₂ with enough water to produce a total volume of 250.00 mL?

A)2.40
B)2.70
C)11.30
D)11.60

Question 43

What is the hydroxide ion concentration of a lye solution that has a pH of 11.20?

A)6.31 × 10^-12 M
B)1.58 × 10^-3 M
C)2.80 M
D)11.20 M

Question 44

What is the pH of a solution made by mixing 100.00 mL of 0.20 M HCl with 50.00 mL of 0.10 M HCl? Assume that the volumes are additive.

A)0.15
B)0.52
C)0.78
D)1.70

Question 45

What is the pH of a 0.020 M Ba(OH)₂ solution?

A)1.40
B)1.70
C)12.30
D)12.60

Question 46

At 25°C,the pH of a vinegar solution is 2.60.What are the values of [H₃O⁺] and [OH^-] in the solution?

A)3.99 × 10^-12 M,2.51 × 10^-3 M
B)2.51 × 10^-3 M,3.98 × 10^-12 M
C)2.51 × 10^-3 M,11.40 M
D)2.60 M,11.40 M

Question 47

Which of the following solutions has the highest concentration of hydroxide ions [OH^-]?

A)pH = 3.21
B)pH = 7.83
C)pH = 10.93
D)pH = 12.04

Question 48

Which of the following indicates the most basic solution?

A)[H⁺] = 1 × 10^{-10 M}
B)pOH = 6.7
C)[OH^-] = 7 × 10^{-5 M}
D)pH = 4.2

Question 49

What is the approximate pH of a solution X that gives the following responses with the indicators shown?

A)3.2 - 4.4
B)4.8 - 6.0
C)6.0 - 7.6
D)8.2 - 10.0

Question 50

What is the approximate pH of a solution X that gives the following responses with the indicators shown?

A)4.8 - 6.0
B)6.0 - 7.6
C)7.6 - 8.2
D)> 8.2

Question 51

The pH of 0.255 M HCN is 4.95.What is the value of K_a for hydrocyanic acid?

A)1.3 × 10^-10
B)4.9 × 10^-10
C)1.1 × 10^-5
D)4.4 × 10^-5

Question 52

What is the approximate pH of a solution X that gives the following responses with the indicators shown?

A)3.2 - 4.4
B)4.8 - 6.0
C)6.0 - 7.6
D)8.2 - 10.0

Question 53

What is the pH of a solution prepared by diluting 25.00 mL of 0.10 M HCl with enough water to produce a total volume of 100.00 mL?

A)1.00
B)1.60
C)2.00
D)3.20

Question 54

Determine the acid dissociation constant for a 0.10 M acetic acid solution that has a pH of 2.87.Acetic acid is a weak monoprotic acid and the equilibrium equation of interest is CH₃COOH(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ CH₃CO₂^-(aq).

A)1.3 × 10^-2
B)1.3 × 10^-3
C)1.8 × 10^-5
D)1.8 × 10^-6

Question 55

Determine the acid dissociation constant for a 0.010 M nitrous acid solution that has a pH of 2.70.Nitrous acid is a weak monoprotic acid and the equilibrium equation of interest is HNO₂(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ NO₂^-(aq).

A)8.0 × 10^-3
B)2.0 × 10^-3
C)5.0 × 10^-4
D)4.0 × 10^-4

Question 56

What is the equilibrium constant expression (K_a)for the acid dissociation of hydrocyanic acid HCN? The equation of interest is HCN(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ CN^-(aq).

A)K_a = ([H₃O⁺][CN^-])/([HCN][H₂O])
B)K_a = ([H₃O⁺][CN^-])/([HCN])
C)K_a = ([HCN][H₂O])/([H₃O⁺][CN^-])
D)K_a = ([HCN])/([H₃O⁺][CN^-])

Question 57

What is the pH of a 0.020 M HClO₄ solution?

A)0.020
B)0.040
C)1.70
D)12.30

Question 58

Determine the acid dissociation constant for a 0.020 M formic acid solution that has a pH of 2.74.Formic acid is a weak monoprotic acid and the equilibrium equation of interest is HCOOH(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ HCO₂^-(aq).

A)1.8 × 10^-3
B)1.8 × 10^-4
C)3.6 × 10^-4
D)3.6 × 10^-5

Question 59

What is the pH of a solution prepared by dissolving 0.15 gram of solid CaO (lime)in enough water to make 2.00 L of aqueous Ca(OH)₂ (limewater)? CaO(s)+ H₂O(l)→ Ca²⁺(aq)+ 2 OH^-(aq)

A)2.57
B)2.87
C)11.13
D)11.43

Question 60

What is the equilibrium constant expression (K_a)for the acid dissociation of nitrous acid HNO₂? The equation of interest is HNO₂(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ NO₂^-(aq).

A)K_a = ([H₃O⁺][NO₂^-])/([HNO₂][H₂O])
B)K_a = ([H₃O⁺][NO₂^-])/([HNO₂])
C)K_a = ([HNO₂][H₂O])/([H₃O⁺][NO₂^-])
D)K_a = ([HNO₂])/([H₃O⁺][NO₂^-])

Question 61

What is the percent dissociation of a benzoic acid solution with pH = 2.59? The acid dissociation constant for this monoprotic acid is 6.5 × 10^-5.

A)0.50%
B)1.5%
C)2.5%
D)3.5%

Question 62

Benzoic acid (C₆H₅CO₂H = HBz)solutions are sometimes used in experiments to determine the molarity of a basic solution of unknown concentration.What is the pH of a 0.100 M solution of benzoic acid if K_a = 6.5 × 10^-5 and the equilibrium equation of interest is HBz(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ Bz^-(aq).

A)1.00
B)2.59
C)4.19
D)5.19

Question 63

A tablet containing 500.0 mg of aspirin (acetylsalicylic acid or HC₉H₇O₄)was dissolved in enough water to make 100 mL of solution.Given that K_a = 3.0 × 10^-4 for aspirin,what is the pH of the solution?

A)1.57
B)2.54
C)3.52
D)5.08

Question 64

The pH of 0.150 M CH₃CO₂H,acetic acid,is 2.78.What is the value of K_a for acetic acid?

A)2.8 × 10^-6
B)1.9 × 10^-5
C)1.7 × 10^-3
D)1.1 × 10^-2

Question 65

Calculate the concentration of bicarbonate ion,HCO₃^-,in a 0.010 M H₂CO₃ solution that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

A)6.6 × 10^-5 M
B)4.3 × 10^-7 M
C)4.3 × 10^-9 M
D)5.6 × 10^-11 M

Question 66

The percent dissociation of acetic acid changes as the concentration of the acid decreases.A 100-fold decrease in acetic acid concentration results in a ________ fold ________ in the percent dissociation.

A)10,increase
B)10,decrease
C)100,increase
D)100,decrease

Question 67

What is the strongest monoprotic acid of the following set if all the acids are at 0.100 M concentration?

A)hydrofluoric acid with K_a = 3.5 × 10^-4
B)benzoic acid with K_a = 6.5 × 10^-5
C)acetic acid with K_a = 1.8 × 10^-5
D)hypochlorous acid with K_a = 3.5 × 10^-8

Question 68

What is the pH of a 0.10 M H₂Se solution that has the stepwise dissociation constants K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

A)2.44
B)3.89
C)4.89
D)5.50

Question 69

Vinegar is a 5.0% solution by weight of acetic acid (CH₃CO₂H)in water.Given that K_a = 1.8 × 10^-5 for acetic acid and assuming the density of vinegar to be 1.00 g/cm³,what is the pH of this vinegar solution?

A)2.00
B)2.41
C)2.87
D)4.74

Question 70

What is the hydronium ion concentration of a 0.100 M acetic acid solution with a K_a = 1.8 × 10^-5? The equation for the dissociation of acetic acid is: CH₃CO₂H(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ CH₃CO₂^-(aq).

A)1.3 × 10^-2 M
B)4.2 × 10^-2 M
C)1.3 × 10^-3 M
D)4.2 × 10^-3 M

Question 71

What is the selenide ion concentration [Se^2-] for a 0.100 M H₂Se solution that has the stepwise dissociation constants of K_a1 = 1.3 × 10^-4 and K_a2 = 1.0 × 10^-11?

A)3.6 × 10^-3 M
B)1.3 × 10^-4 M
C)1.3 × 10^-5 M
D)1.0 × 10^-11 M

Question 72

Calculate the pH of a 0.20 M H₂SO₃ solution that has the stepwise dissociation constants K_a1 = 1.5 × 10^-2 and K_a2 = 6.3 × 10^-8.

A)1.26
B)1.32
C)1.82
D)2.52

Question 73

Calculate the pH of a 0.020 M carbonic acid solution,H₂CO₃(aq),that has the stepwise dissociation constants K_a1 = 4.3 × 10^-7 and K_a2 = 5.6 × 10^-11.

A)1.70
B)4.03
C)6.37
D)10.25

Question 74

Which of the following can be classified as a weak base?

A)CH₃NH₂
B)NH₂OH
C)Both CH₃NH₂ and NH₂OH
D)Neither CH₃NH₂ nor NH₂OH

Question 75

Para-Aminobenzoic acid (PABA),p-H₂NC₆H₄(COOH),is used in some sunscreens and hair conditioning products.Calculate the pH of an aqueous solution with [PABA] = 0.030 M and K_a = 2.2 × 10^-5.

A)1.52
B)3.09
C)4.66
D)6.18

Question 76

Potassium hydrogen phthalate (molar mass = 204.2 g/mol)is one of the most commonly used acids for standardizing solutions containing bases.KHP is a monoprotic weak acid with K_a = 3.91 × 10^-6.Calculate the pH of the solution that results when 0.40 g of KHP is dissolved in enough water to produce 25.0 mL of solution.

A)2.10
B)3.26
C)4.30
D)5.41

Question 77

Vinegar is a 5.0% solution by weight of acetic acid (CH₃CO₂H)in water.Given that the pH for acetic acid is 2.41,the K_a = 1.8 × 10^-5 and assuming the density of vinegar to be 1.00 g/cm³,what is the percent dissociation of acetic acid in vinegar?

A)0.47%
B)1.5%
C)4.0%
D)5.0%

Question 78

What is the hydronium ion concentration of a 0.100 M hypochlorous acid solution with K_a = 3.5 × 10^-8? The equation for the dissociation of hypochlorous acid is: HOCl(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ OCl^-(aq).

A)1.9 × 10^-4
B)5.9 × 10^-4
C)1.9 × 10^-5
D)5.9 × 10^-5

Question 79

What is the second stepwise equilibrium constant expression for phosphoric acid H₃PO₄?

A)K_a2 = ([H₃O⁺][H₂PO₄^-])/([H₃PO₄])
B)K_a2 = ([H₃O⁺]2[HPO₄^2-])/([H₃PO₄])
C)K_a2 = ([H₃O⁺]3[PO₄^3-])/([H₃PO₄])
D)K_a2 = ([H₃O⁺][HPO₄^2-])/([H₂PO₄^-])

Question 80

What is the pH of a 0.100 M NH₃ solution that has K_b = 1.8 × 10^-5? The equation for the dissociation of NH₃ is NH₃(aq)+ H₂O(l)⇌ NH₄⁺(aq)+ OH^-(aq).

A)1.87
B)2.87
C)11.13
D)12.13