Deck 16: Acids and Bases

Question 1

In the equilibrium system described by: PO43-(aq) + H2O(l) ⇌ HPO42-(aq) + OH-, Br∅nsted-Lowry theory would designate:

A) PO43- and H2O as the bases
B) H2O and OH- as a conjugate pair
C) HPO42- and OH- as the acids
D) HPO42- and H2O as a conjugate pair
E) PO43- as amphiprotic

Answer 1

H2O and OH- as a conjugate pair

Question 2

Which of the following is the strongest base?

A) Cl-
B) ClO4-
C) F-
D) NO3-
E) H2O

Answer 2

F-

Question 3

In the reaction BF₃ + NH₃ → F₃B:NH₃, BF₃ acts as a Br∅nsted acid.

Answer 3

False

Question 4

Amine bases are known as strong bases

Question 5

The definition of a neutralization reaction as a reaction in which an acid reacts with a base to produce water and a salt is inherent in:

A) only the Arrhenius theory
B) both the Arrhenius and the Br∅nsted-Lowry theories
C) only the Br∅nsted-Lowry theory
D) both the Br∅nsted-Lowry and the Lewis theories
E) only the Lewis theory

Question 6

Proton acceptor is an abbreviated definition of:

A) Br∅nsted-Lowry base
B) Br∅nsted-Lowry acid
C) Lewis base
D) Lewis acid
E) Arrhenius acid

Question 7

According to the Arrhenius theory, a neutralization reaction involves:

A) the combination of hydrogen ions and hydroxide ions to form water.
B) the dissociation of a strong acid to hydrogen ions and an anion.
C) the dissociation of a strong base into hydroxide ions and a cation.
D) the addition of water to ammonia to make ammonium hydroxide.
E) the combination of an acid with a base to make only water.

Question 8

Choose the Br∅nsted-Lowry acids and bases in the following equation: HCN + OH- ⇌ H2O + CN-

A) acids HCN, CN- bases OH-, H2O
B) acids CN-, OH- bases HCN, H2O
C) acids HCN, H2O bases OH-, CN-
D) acids OH-, H2O bases CN-, HCN
E) acids HCN, OH- bases H2O, CN-

Question 9

H₂SO₄ is a weaker acid than H₂SO₃.

Question 10

When comparing binary acids of the elements in the same row of the periodic table, acid strength increases as the polarity of the element-hydrogen bond increases.

Question 11

According to the Arrhenius theory, a neutralization reaction involves the combination of hydrogen ions and hydroxide ions to form water.

Question 12

Choose the strongest acid.

A) HF
B) H2CO3
C) HCN
D) HC2H3O2
E) HClO4

Question 13

Br∅nsted and Lowry suggested that bases be defined as proton acceptors.

Question 14

The first ionization step is approximately 100% for H₂SO₃.

Question 15

The term pH = -ln [H+].

Question 16

Which of the following are Br∅nsted-Lowry acid?
I. CH₃COOH
II. [Cu(H₂O)₄]²⁺
III. H₂O
IV. CH₃NH₂
V. H₃O+

A) I), II) and III)
B) II), III), and IV)
C) I), II), III) and IV)
D) I), II), III), and V)
E) II), III) and V)

Question 17

HNO₃ is a strong acid.

Question 18

Choose the INCORRECT statement.

A) H2SO4, HCl, and HNO3 all form H3O+ when reacted with H2O.
B) Neutralization takes place when the hydronium ion reacts with the hydroxide ion to form water.
C) Br∅nsted and Lowry suggested that bases be defined as proton acceptors.
D) The odor that is noticeable when the stopper is removed from a bottle of aqueous ammonia is good evidence of the strength of the substance as a base.
E) Br∅nsted and Lowry suggested that acids be defined as proton donors.

Question 19

According to the Arrhenius theory, a neutralization reaction involves the combination of an acid with a base to make only water.

Question 20

pOH = 3.14 is equivalent to:

A) pH = 11.
B) [H+] = 1.4 × 10-10 M
C) [OH-] = 7.2 × 10-4 M
D) [H+} = 7.0 × 10-4 M
E) [OH-] = 3.14 × 10-7 M

Question 21

A 0.0925 g sample of a monoprotic base (mm = 17.03 g/mol) was dissolved in water to produce 100 mL of solution with a pH = 11.00. What is the ionization constant of this base?

A) 1.8 × 10-6
B) 1.8 × 10-11
C) 1.8 × 10-21
D) 1.9 × 10-5
E) 1.1 × 10-6

Question 22

A 0.214 M solution of a monoprotic base has a pH of 11.48. What is the ionization constant of this base?

A) 1.4 × 10-2
B) 4.3 × 10-5
C) 1.5 × 10-11
D) 5.1 × 10-23
E) 2.0 × 10-6

Question 23

Choose the Br∅nsted-Lowry acids and bases in the following equation: H2O + NH2- ⇌ NH3 + OH-

A) acids H2O, OH- bases NH3, NH2-
B) acids NH2-, NH3 bases H2O, OH-
C) acids H2O, NH2- bases OH-, NH3
D) acids NH3, NH2- bases OH-, H2O
E) acids H2O, NH3 bases NH2-, OH-

Question 24

A saturated aqueous solution of calcium hydroxide has a pH of 12.25. What is the [Ca2+] of such a solution?

A) 0.018
B) 5.6 × 10-13
C) 2.3 × 10-5
D) 0.035
E) 8.9 × 10-3

Question 25

What is the [HPO4-2] of a solution labeled "0.10 M Phosphoric Acid"? [Ka1 = 7.1 × 10-3; Ka2 = 6.3 × 10-8; Ka3 = 4.2 × 10-13]

A) 4.2 × 10-13 M
B) 6.3 × 10-8 M
C) 7.1 × 10-3 M
D) 1.6 × 10-9 M
E) 1.6 × 10-16 M

Question 26

A 0.505 g sample of a monoprotic base (mm = 45.09 g/mol) was dissolved in water to produce 100.0 mL of solution with a pH = 11.84. What is the ionization constant of this base?

A) 4.3 × 10-5
B) 1.9 × 10-23
C) 4.3 × 10-4
D) 3.4 × 10-1
E) 1.3 × 10-11

Question 27

At 25°C, the pH of pure water is:

A) 0
B) >0, <7
C) 7
D) >7, <14
E) 14

Question 28

Choose the Br∅nsted-Lowry acids and bases in the following equation: HSO4- + C2H3O2- ⇌ HC2H3O2 + SO42-

A) acids HSO4-, SO42- bases HC2H3O2, C2H3O2-
B) acids HSO4-, HC2H3O2 bases SO42-, C2H3O2-
C) acids SO42-, HC2H3O2 bases HSO4-, C2H3O2-
D) acids SO42-, C2H3O2- bases HSO4-, HC2H3O2
E) acids HSO4-, C2H3O2- bases HC2H3O2, SO42-

Question 29

Choose the Br∅nsted-Lowry acids and bases in the following equation: NH4+ + OH- ⇌ H2O + NH3

A) acids NH4+, OH- bases H2O, NH3
B) acids OH-, H2O bases NH3, NH4+
C) acids NH4+, OH- bases NH4+, H2O
D) acids NH4+, H2O bases OH-, NH3
E) acids NH4+, NH3 bases OH-, H2O

Question 30

0.653 g of a monoprotic acid (mm = 157 g/mol) is dissolved in water to produce 50.0 mL of a solution with pH = 2.13. Determine the ionization constant of the acid.

A) 7.9 × 10-3
B) 8.9 × 10-2
C) 6.6 × 10-4
D) 3.9 × 10-2
E) 3.6 × 10-6

Question 31

What is the [AsO43-] for a solution labeled 0.10 M arsenic acid (H3AsO4)? [Ka1 = 6 × 10-3, Ka2 = 1 × 10-7, Ka3 = 3 × 10-12]

A) 1 × 10-7 M
B) 1 × 10-17 M
C) 3 × 10-12 M
D) 3 × 10-19 M
E) 6 × 10-10 M

Question 32

Consider the reaction: HC2H3O2 + H2O ⇌ H3O+ + C2H3O2-
Choose the pair of substances that are both bases in the reaction.

A) HC2H3O2 and H3O+
B) H2O and C2H3O2-
C) H2O and H3O+
D) HC2H3O2 and C2H3O2-
E) H3O+ and HC2H3O2

Question 33

Choose the INCORRECT statement. The term pH:

A) refers to the "potential" of hydrogen ion
B) = -ln [H+]
C) = 14 - pOH
D) is more convenient than exponential notation
E) = -log [H3O+]

Question 34

Which of the following statements is NOT true?

A) In liquid ammonia, the strongest possible base is the NH2- ion.
B) Ammonium hydroxide and acetic acid have equal ionization constants in water at 25 °C because of the leveling effect.
C) The second ionization constant of a diprotic acid is always smaller than the first ionization constant.
D) A Br∅nsted base may be any substance that can act as a proton acceptor.
E) Bases neutralize acids to form salts plus water.

Question 35

A solution has pOH of -0.47. This means that:

A) the solution has a pH of 13.53
B) the solution has an [OH-] = 0.34 M
C) the solution has an [OH-] greater than 10.0 M
D) the solution has an [OH-] = 2.95 M
E) The solution has an [H+] = 2.95 M

Question 36

0.272 g of a monoprotic acid (Mw = 189 g/mol) is dissolved in water to produce 25.0 mL of a solution with pH = 4.93. Determine the ionization constant of the acid.

A) 4.1 × 10-8
B) 1.4 × 10-10
C) 2.1 × 10-4
D) 2.8 × 10-7
E) 2.4 × 10-9

Question 37

Choose the Br∅nsted-Lowry acids and bases in the following equation: HCO3- + OH- ⇌ H2O + CO32-

A) acids HCO3-, H2O bases OH-, CO32-
B) acids OH-, CO32- bases HCO3-, H2O
C) acids H2O, OH- bases HCO3-, CO32-
D) acids HCO3-, OH- bases CO32-, H2O
E) acids H2O, CO32- bases HCO3-, OH-

Question 38

A 0.632 M solution of a monoprotic base has a pH of 11.53. What is the ionization constant of this base?

A) 1.8 × 10-5
B) 2.1 × 10-3
C) 1.6 × 10-23
D) 5.0 × 10-12
E) 5.3 × 10-3

Question 39

0.375 g of a monoprotic acid (mm = 245 g/mol) is dissolved in water to produce 25.0 mL of a solution with pH = 3.28. Determine the ionization constant of the acid.

A) 8.56 × 10-3
B) 4.5 × 10-6
C) 7.4 × 10-5
D) 4.5 × 10-3
E) 2.3 × 10-2

Question 40

For which of the following polyprotic acids is the first ionization step approximately 100%?

A) H2S
B) H2SO3
C) H2CO3
D) H2SO4
E) H3PO4

Question 41

In which of the following cases is water acting as a base under the Lewis definitions, but not under the Br∅nsted-Lowry definitions?

A) H2O(l) + HF(g) ⇌ H3O+(aq) + F(aq)
B) H2O(l)+ CN-(aq) ⇌ OH-(aq) + HCN(aq)
C) H2O(l) + Cu2+(aq) ⇌ Cu(H2O)2+(aq)
D) H2O(l) + PO43-(aq) ⇌ 2OH-(aq) + H2PO4-(aq)
E) H2O(l) [electrolysis] ⇌ 2H2(g) + O2(g)

Question 42

Which of the following statements concerning aqueous solutions of salts is FALSE?

A) For any salt of a strong acid and a strong base, the pH will be about 7.
B) For any salt of a strong acid and a weak base, the pH will be <7.
C) For any salt of a weak acid and a strong base, the pH will be >7.
D) For any salt of a weak acid and a weak base, the pH will be about 7.

Question 43

The pH of a solution of NH4C2H3O2 is approximately 7. The best explanation is:

A) This salt does not react with water.
B) Ammonium acetate is a weak electrolyte.
C) All salts of weak acids and weak bases are neutral.
D) Aqueous ammonia and acetic acid have approximately equal ionization constants.
E) The salt is a product of a strong acid and a strong base.

Question 44

Complete the following equation. List the conjugate acid base pairs. Put the base first in each pair. HCl + NH3 ⇌

A) Cl- + NH4+ (NH3, NH4+) (Cl-, HCl)
B) Cl- + NH4+ (NH3, HCl) (Cl-, NH4+)
C) H2 + Cl- + NH2- (NH3, NH2-) (Cl-, HCl)
D) H2Cl+ + NH2- (NH3, NH2-) (HCl, H2Cl)
E) Cl- + NH4+ (NH3, Cl-) (NH4+, HCl)

Question 45

In the reaction BF3 + NH3 ⇌ F3B:NH3, BF3 acts as:

A) an Arrhenius base
B) a Lewis base
C) a Br∅nsted acid
D) a Lewis acid
E) an Arrhenius acid

Question 46

A 250.0 ml sample of gaseous hydrogen bromide, measured at 22.9°C and 0.930 atm, was dissolved in sufficient pure water to form 250.0 ml of solution. What was the pH of that solution?

A) 1.42
B) 2.58
C) 3.83
D) 4.18
E) 5.68

Question 47

Which of the following are Lewis bases?
I. BCl₃
II. H-
III. H₂O
IV. NH₃
V. AlCl₃

A) II), III) and IV)
B) I), II), and III)
C) III), IV) and V)
D) I), II), and V)
E) I), II), and IV)

Question 48

In the following reversible reaction the Br∅nsted acids are ________. HCO3-(aq) + OH-(aq) ⇌ CO32-(aq) + H2O

A) HCO3- and H2O
B) HCO3- and CO32-
C) OH- and CO32-
D) OH- and H2O
E) H2O and CO32-

Question 49

What is the [OH-] of a solution prepared by dissolving 0.0912 g of hydrogen chloride in sufficient pure water to prepare 250.0 ml of solution?

A) 10-2 M
B) 10-8 M
C) 10-12 M
D) 10-4 M
E) 1.0 M

Question 50

Which species in the following reaction acts as a Lewis acid? CuSO4(s) + 4NH3(aq) ⇌ [Cu(NH3)4]2+(aq) + SO42-(aq)

A) SO42-
B) Cu2+
C) [Cu(NH3)4]2+(aq)
D) NH3
E) [Cu(NH3)4]2+(aq) and SO42-

Question 51

What is the pH of a solution prepared by dissolving 0.140 g of potassium hydroxide in sufficient pure water to prepare 250.0 ml of solution?

A) 2
B) 6
C) 10
D) 12
E) 14

Question 52

What would be the pH of a solution prepared by dissolving 14.4 g NaOH (Mw = 40.0 g/mol) in enough water to make 1.05 L of solution?

A) 13.54
B) 0.46
C) 13.58
D) 13.66
E) 7.00

Question 53

The concept of an acid not limited to H+ or species containing one or more protons is inherent in:

A) only the Arrhenius theory
B) both the Arrhenius and the Br∅nsted-Lowry theories
C) only the Br∅nsted-Lowry theory
D) both the Br∅nsted-Lowry and the Lewis theories
E) only the Lewis theory

Question 54

What is the [K+] of a solution prepared by dissolving 0.140 g of potassium hydroxide in sufficient pure water to prepare 250.0 ml of solution?

A) 10-5 M
B) 10-8 M
C) 10-12 M
D) 10-4 M
E) 10-2 M

Question 55

Which of the following is a logical inference from the fact that a 0.10 molar solution of potassium acetate, KC2H3O2, is less alkaline than a 0.10 molar solution of potassium cyanide, KCN?

A) Hydrocyanic acid is a weaker acid than acetic acid.
B) Cyanides are less soluble than acetates.
C) Hydrocyanic acid is less soluble in water than acetic acid.
D) Acetic acid is a weaker acid than hydrocyanic acid.
E) 0.10 M potassium acetate is more concentrated than 0.10 M potassium cyanide.

Question 56

What is the [Cl-] of a solution prepared by dissolving 0.1824 g of hydrogen chloride in sufficient pure water to prepare 500.0 ml of solution?

A) 10-2 M
B) 10-8 M
C) 10-12 M
D) 10-4 M
E) 1.0 M

Question 57

Determine the pH of 263 ml of solution which has [NH4I] = 0.300 M. Kb = 1.74 × 10-5 for NH3(aq).

A) 2.6
B) 11.4
C) 4.9
D) 9.1
E) 4.6

Question 58

For the following compound, predict whether the solution is acidic, basic or neutral and why: HI.

A) acidic because HI is a strong acid
B) basic because HI is a weak base
C) neutral because there is no hydrolysis
D) basic because HI is the salt of a weak acid
E) acidic because HI is the salt of a weak base

Question 59

If one mole of Ba(OH)2 is added to enough water to make 10 liters of solution, the pH of the resulting solution is ________.

A) 13.3
B) 1.0
C) 0.7
D) 13.0
E) 12.5

Question 60

Which indication of relative acid strengths is INCORRECT?

A) HCl > HF
B) HClO2 > HClO
C) H2SO4 > H2SO3
D) H2SO3 > HNO3
E) CH3CO2H > CH3CH2OH

Question 61

The ionization constant for ammonia is 1.8 × 10-5. What is the pH of a solution labeled 0.50 M ammonia?

A) 7.30
B) 9.12
C) 10.26
D) 11.48
E) 12.52

Question 62

What is the pH of a solution labeled "0.10 M Phosphoric Acid"? [Ka1 = 7.1 × 10-3; Ka2 = 6.3 × 10-8; Ka3 = 4.2 × 10-13]

A) 5.7
B) 4.3
C) 3.1
D) 2.3
E) 1.6

Question 63

A saturated aqueous solution of calcium hydroxide is approximately 0.13% calcium hydroxide, by mass, and has a density of 1.02 g ml-1. What is the pH of such a solution?

A) 11.95
B) 12.25
C) 12.55
D) 12.75
E) 13.00

Question 64

What is the pH for a solution labeled 0.10 M arsenic acid (H3AsO4)? [Ka1 = 6 × 10-3, Ka2 = 1 × 10-7, Ka3 = 3 × 10-12]

A) 1.6
B) 4.0
C) 6.3
D) 1.0
E) 3.2

Question 65

What is the pH of a 0.375 M solution of benzoic acid? Ka = 6.3 × 10-5

A) 8.9
B) 5.1
C) 2.3
D) 0.43
E) 11.7

Question 66

What is the pH of a 0.570 M solution of aniline? Kb = 7.4 × 10-10

A) 11.4
B) 2.6
C) 9.4
D) 4.7
E) 9.3

Question 67

For the following compound, predict whether the solution is acidic, basic or neutral and why: NaC2H3O2.

A) acidic because NaC2H3O2 is a strong acid
B) basic because NaC2H3O2 is a weak base
C) neutral because there is no hydrolysis
D) basic because NaC2H3O2 is the salt of a weak acid
E) acidic because NaC2H3O2 is the salt of a weak base

Question 68

For the following compound, predict whether the solution is acidic, basic or neutral and why: Na2CO3.

A) acidic because Na2CO3 is a strong acid
B) basic because Na2CO3 is a weak base
C) neutral because there is no hydrolysis
D) basic because Na2CO3 is the salt of a weak acid
E) acidic because Na2CO3 is the salt of a weak base

Question 69

The Kb value for methylamine is 4.2 × 10-4. What is the pH of an aqueous solution for which the label reads "0.042 M CH3NH2"?

A) 2.4
B) 4.8
C) 9.2
D) 11.6
E) 12.3

Question 70

For the following compound, predict whether the solution is acidic, basic or neutral and why: NH3.

A) acidic because NH3 is a strong acid
B) basic because NH3 is a weak base
C) neutral because there is no hydrolysis
D) basic because NH3 is the salt of a weak acid
E) acidic because NH3 is the salt of a weak base

Question 71

What is the concentration of free sulfate ion in a solution labeled "3.6M H2SO4"? [Ka2 = 1.1 × 10-2]

A) 0.011 M
B) 0.040 M
C) 0.20 M
D) 0.60 M
E) 1.8 M

Question 72

What is the pH of a 0.250 M solution of formic acid? Ka = 1.8 × 10-4

A) 11.8
B) 2.2
C) 0.60
D) 5.4
E) 8.6

Question 73

What is the [H2AsO4-] for a solution labeled 0.10 M arsenic acid (H3AsO4)? [Ka1 = 6 × 10-3, Ka2 = 1 × 10-7, Ka3 = 3 × 10-12]

A) 1 × 10-7
B) 6 × 10-3
C) 0.02
D) 0.08
E) 6 × 10-10

Question 74

What is the [H2PO4-] of a solution labeled "0.10 M Phosphoric Acid"? [Ka1 = 7.1 × 10-3; Ka2 = 6.3 × 10-8; Ka3 = 4.2 × 10-13]

A) 0.023 M
B) 6.3 × 10-8 M
C) 7.1 × 10-3 M
D) 4.2 × 10-13 M
E) 0.013 M

Question 75

What is the pH of a 0.470 M solution of pyridine? Kb = 1.5 × 10-9

A) 9.6
B) 11.2
C) 2.8
D) 9.4
E) 4.6

Question 76

For the following compound, predict whether the solution is acidic, basic or neutral and why: NH4Cl.

A) acidic because NH4Cl is a strong acid
B) basic because NH4Cl is a weak base
C) neutral because there is no hydrolysis
D) basic because NH4Cl is the salt of a weak acid
E) acidic because NH4Cl is the salt of a weak base

Question 77

What is the pH of a 0.380 M solution of ethylamine? Kb = 4.3 × 10-4

A) 12.1
B) 1.9
C) 10.2
D) 5.5
E) 8.5

Question 78

For the following compound, predict whether the solution is acidic, basic or neutral and why: NaCl.

A) acidic because NaCl is a strong acid
B) basic because NaCl is a weak base
C) neutral because there is no hydrolysis
D) basic because NaCl is the salt of a weak acid
E) acidic because NaCl is the salt of a weak base

Question 79

Hypochlorous acid (HOCl) has an ionization constant of 3.2 × 10-8. What is its percent ionization in 1.0 M and 0.10 M solutions, respectively?

A) 0.018% and 0.057%
B) 0.032% and 0.0032%
C) 0.57% and 0.18%
D) 0.57% in both
E) 0.32% in both

Question 80

What is the pH of a 0.530 M solution of hypochlorus acid? Ka = 2.9 × 10-8

A) 10.6
B) 3.4
C) 10.1
D) 3.9
E) 0.28