Deck 4: Acids and Bases

Question 1

Which of the following compounds is the strongest acid?

A) CH₃COOH
B) FCH₂COOH
C) ClCH₂COOH
D) BrCH₂COOH

Answer 1

FCH₂COOH

Question 2

Which of the following compounds is the strongest acid?

A) HF
B) H₂O
C) NH₃
D) CH₄

Answer 2

HF

Question 3

Which of the following compounds is the strongest acid?

A) CH₃OCH₃
B) CH₃CH₂OH
C) CH₃CHO
D) CH₃CO₂H

Answer 3

CH₃CO₂H

Question 4

Which of the following is easiest to deprotonate?

A) CH₄
B) CH₃CH₃
C) CH₂=CH₂
D) HC≡CH

Question 5

Which of the following anions is the strongest base?

A) NH₂−
B) NH₃
C) CH₃CH=N−
D) CH₃C≡N

Question 6

Which of the following compounds is the strongest acid?

A) CH₃CH₂CH₂COOH
B) CH₃CH₂CHClCOOH
C) CH₃CHClCH₂COOH
D) ClCH₂CH₂CH₂COOH

Question 7

Which of the following compounds is the strongest acid?

A) CF₃OH
B) CF₃CH₂ CH₂OH
C) CF₃CH₂ CH₂ CH₂OH
D) CF₃CH₂ CH₂ CH₂CH₂OH

Question 8

The pK_a of acetic acid, CH₃COOH, is 4.76. What is the value of the equilibrium constant K_eq, for the following equilibrium? [The concentration of water in a dilute aqueous solution is 55 M] $\mathrm{CH}_{3} \mathrm{COOH}+\mathrm{H}_{2} \mathrm{O}=\mathrm{H}_{3} \mathrm{O}^{\oplus}+\mathrm{CH}_{3} \mathrm{COO}^{\ominus}$

A) 3.2 × 10⁷
B) ?3.2 × 10?⁷
C) ?3.2 × 10⁷
D) 3.2 × 10?⁷

Question 9

Which of the following is the strongest base?

A) iodide anion, I−
B) fluoride anion, F−
C) bromide anion, Br−
D) chloride anion, Cl−

Question 10

Which of the following is the strongest acid?

A) CH₃NH₂
B) CH₃PH₂
C) CH₃OH
D) CH₃SH

Question 11

Which of the following anions is the strongest base?

A) CH₃COO−
B) HO−
C) NH₂−
D) Cl−

Question 12

Which of the following is the strongest acid?

A) CH₃CH₃
B) CH₃NH₂
C) CH₃OH
D) CH₃F

Question 13

The pK_a of HCl is ?7. What is the value of the equilibrium constant, K_eq, for the following equilibrium? [The concentration of water in a dilute aqueous solution is 55 M] $\mathrm{HCl}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{3} \mathrm{O}^{\oplus}+\mathrm{Cl}^{\ominus}$

A) 1.8 × 10⁵
B) 385
C) 1.8 × 10?⁵
D) ?1.8 × 10⁵

Question 14

Which of the following is the strongest acid?

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

Question 15

Which of the following compounds is the strongest acid?

A) CH₄
B) CH₃CH₃
C) H₂C=CH₂
D) HC≡CH

Question 16

Which of the following compounds has the highest pK_a?

A) SiH₄
B) H₂S
C) PH₃
D) HCl

Question 17

Which of the following is the strongest base?

A) NaOH
B) NaCO₃
C) H₂O
D) CH₃OH

Question 18

Which of the following compounds is the strongest acid?

A) CH₃COOH
B) ClCH₂COOH
C) CH₃CH₂OH
D) ClCH₂CH₂OH

Question 19

Which of the following is the correct order of decreasing basicity (stronger base > weaker base)?

A) NH₃ > MeNH₂ > H₂O > HF
B) MeNH₂ > NH₃ > MeOH > CH₄
C) NH₃ > Me₃N > H₂O > MeOH
D) CH₃COONa > NaOH > NaOMe > NaNMe₂

Question 20

Which of the following is the strongest acid?

A) CH₃OH
B) CH₃CHO
C) CH₃COCH₃
D) CH₃COOH

Question 21

What is the value of the equilibrium constant, K_eq, for the following reaction?

A) 10⁹
B) 10−⁹
C) 9
D). ¹/₉

Question 22

Which sets of curved arrows accounts for the protonation of propene with HI?

A) 1
B) 2
C) 3
D) 4

Question 23

Which of the following compounds has the lowest pK_a?

A) H₂O
B) HBr
C) NH₃
D) CH₄

Question 24

Which of the following is present in the highest concentration upon dissolution of acetic acid in water?

A) OH−
B) H₃O⁺
C) CH₃COOH
D) CH₃COOH⁺

Question 25

Which of the following terms describes the reactivity of boron tribromide, BBr₃?

A) Brønsted-Lowry acid and Lewis acid
B) Brønsted-Lowry base and Lewis base
C) Lewis acid and not a Brønsted-Lowry acid
D) Lewis base and not a Brønsted-Lowry base

Question 26

Which species is the conjugate acid in the following acid-base reaction?

A) 1
B) 2
C) 3
D) 4

Question 27

Which set of curved arrows accounts for the deprotonation of an acid (A-H) by a base (:B)?

A) 1
B) 2
C) 3
D) 4

Question 28

Which of the following is a Lewis acid but not a Brønsted-Lowry acid?

A) CH₃COOH
B) AlCl₃
C) H₂O
D) CH₃OH

Question 29

Which of the following terms describes the role of ethyne in the acid-base reaction shown?

A) Brønsted-Lowry acid
B) Brønsted-Lowry base
C) Lewis acid
D) Lewis base

Question 30

Which of the following is a feature of a Lewis acid?

A) proton donor
B) proton acceptor
C) electron pair donor
D) electron pair acceptor

Question 31

Which of the following compounds has the highest pK_a?

A) NH₃
B) H₂O
C) HCl
D) CH₄

Question 32

Which of the following is present in the highest concentration upon dissolution of H₂SO₄ in water?

A) H₂SO₄
B) H⁺
C) H₃O⁺
D) HO−

Question 33

Which of the following terms describes the reactivity of trimethylamine, (CH₃)₃N?

A) Brønsted-Lowry acid and Lewis acid
B) Brønsted-Lowry base and Lewis base
C) Lewis acid and not a Brønsted-Lowry acid
D) Lewis base and not a Brønsted-Lowry base

Question 34

Which species is the conjugate acid in the following acid-base reaction?

A) 1
B) 2
C) 3
D) 4

Question 35

Which of the following terms describes the role of ethanol in the acid-base reaction shown?

A) Brønsted-Lowry acid
B) Brønsted-Lowry base
C) Lewis acid
D) Lewis base

Question 36

Which of the following compounds has the lowest pK_a?

A) H₂O
B) H₂S
C) H₂Se
D) H₂Te

Question 37

Which of the following terms describes the role of ethanol in the acid-base reaction shown?

A) Brønsted-Lowry acid
B) Brønsted-Lowry base
C) Lewis acid
D) Lewis base

Question 38

Which of the following is a feature of a Lewis base?

A) proton donor
B) proton acceptor
C) electron pair donor
D) electron pair acceptor

Question 39

Which of the following terms describes the role of ethene in the acid-base reaction shown?

A) Brønsted-Lowry acid
B) Brønsted-Lowry base
C) Lewis acid
D) Lewis base

Question 40

What is the value of the equilibrium constant, K_eq, for the following reaction?

A) 10¹³
B) 10−¹³
C) 13
D) .¹/₁₃

Question 41

Which of the following statements is not true?

A) The position of the equilibrium for an exergonic reaction favors products
B) The products of an exergonic reaction have a higher Gibbs free energy than the reactants.
C) The equilibrium constant of a reaction for which ΔG° = 0 is 1.
D) ΔG° = ΔH° − TΔS°

Question 42

Which of the following energy diagrams represents the slowest reaction?

A) 1
B) 2
C) 3
D) 4

Question 43

Which of the following is a definition of the activation energy of a reaction?

A) the difference in Gibbs free energy between the reactants and the transition state
B) the difference in Gibbs free energy between the reactants and the intermediate
C) the difference in Gibbs free energy between the reactants and the product
D) the difference in Gibbs free energy between the transition state and the product

Question 44

Which of the following energy diagrams represents the fastest reaction?

A) 1
B) 2
C) 3
D) 4

Question 45

An acid with a low pK_a is a strong acid and has a weak conjugate base.

Question 46

In the following list, there are two organic Lewis bases.
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Question 47

In the following list, there are four Lewis acids, CH₃OH, HCl, BCl₃ and FeBr₃.

Question 48

Which of the following has a pK_a value of approximately 16?

A) HBr
B) CH₃COOH
C) CH₃CH₂OH
D) HC≡CH

Question 49

Which of the following has a pK_a value of approximately 25?

A) CH₃CH₃
B) CH₂=CH₂
C) HC≡CH
D) CH₃CH₂OH

Question 50

Which of the following concepts can be used to rationalize the observation that acetic acid is a stronger acid than methanol?

A) electronegativity
B) resonance
C) valence shell electron pair repulsion theory
D) Pauli exclusion principle

Question 51

What is the approximate pK_a value of acetic acid?

A) −7
B) 5
C) 16
D) 51

Question 52

What is the approximate pK_a value of HCl?

A) −7
B) 5
C) 16
D) 51

Question 53

Which of the following is a feature of a Brønsted-Lowry base?

A) proton donor
B) proton acceptor
C) electron pair donor
D) electron pair acceptor

Question 54

Which of the following is a feature of a Brønsted-Lowry acid?

A) proton donor
B) proton acceptor
C) electron pair donor
D) electron pair acceptor

Question 55

Which of the following equations is correct?

A) ΔG° = ΔH° − TΔS°
B) ΔH° = ΔG° − TΔS°
C) ΔG° = ΔH° − ΔS°
D) ΔG° = ΔH° − ΔS°/T

Question 56

Which of the following has the highest bond dissociation energy?

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

Question 57

Under which of the following conditions will a reaction be spontaneous when ΔH° > 0?

A) TΔS° = 0
B) −TΔS° > ΔH°
C) TΔS° < 0°
D) ΔG° = 0

Question 58

Which of the following is a definition of the rate-determining step of a reaction mechanism?

A) the first step
B) the last step
C) the step that crosses the highest energy barrier
D) the most exothermic step

Question 59

Which of the following energy diagrams best represents the changes in energy during addition of HBr to an alkene?

A) 1
B) 2
C) 3
D) 4

Question 60

Which atom in the following structure is preferentially protonated by a strong acid?

A) i
B) ii
C) iii
D) iv

Question 61

The structure of the alkaloid ephedrine is shown below. When ephedrine is placed in the presence of an acid, the -OH group will be protonated.

Question 62

Use curved arrows to show the movement of pairs of electrons in the following acid-base reaction and show the structures of the conjugate acid and conjugate base.

Question 63

Indole is pleasant smelling in highly dilute solutions and has been used in perfumery. When indole is placed in the presence of a strong base the nitrogen atom will be deprotonated.

Question 64

Use curved arrows to show the movement of pairs of electrons in the following acid-base reaction and show the structures of the conjugate acid and conjugate base.

Question 65

Complete the equation below for the protonation of 2-butene with HBr. Show the movement of pairs of electrons with curved arrows and provide the structures of the conjugate acid and conjugate base.

Question 66

The following is generic depiction of a reaction using the curve arrow formalism. In this reaction electrons move from C to B and A will have a positive charge in the product.

Question 67

What is the value of the equilibrium constant for the following equilibrium?

Question 68

What is the value of the equilibrium constant for the following equilibrium?

Question 69

Consider the following reaction coordinate diagram. The transition state is represented by the letter B.

Question 70

What is the value of the equilibrium constant for the following equilibrium?

Question 71

The following correctly shows the electron flow for the given reaction.

Question 72

What is the value of the equilibrium constant for the following equilibrium?

Question 73

Consider the following reaction coordinate diagram. This reaction is endergonic.

Question 74

Complete the equation below for the protonation of cyclohexene with HCl. Show the movement of pairs of electrons with curved arrows and provide the structures of the conjugate acid and conjugate base.

Question 75

Provide the equation that relates the acid dissociation constant, K_a, to the pK_a of an acid.

Question 76

Indole is pleasant smelling in highly dilute solutions and has been used in perfumery. Indole can be classified as a Brønsted-Lowry base but not as a Lewis base..

Question 77

Provide the equation for the equilibrium constant, K_eq, for the following equilibrium.

Question 78

Consider the following reaction coordinate diagram. The free energy of activation is represented by the letter C.

Question 79

Provide the equation that relates the equilibrium constant, K_eq, to the acid dissociation constant, K_a, for the following equilibrium.

Question 80

Provide the equation for the acid dissociate constant, K_a,for the following equilibrium.