Deck 4: Acids and Bases

Question 1

Which of the following is the strongest base?

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

Answer 1

fluoride anion, F^-

Question 2

Which of the following is the strongest acid?

A) CH₃CH₃
B) CH₃NH₂
C) CH₃OH
D) CH₃F

Answer 2

CH₃OH

Question 3

Which of the following is the strongest acid?

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

Answer 3

HI

Question 4

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]

A) 1.8 * 10⁵
B) 385
C) 1.8 * 10^-5
D) -1.8 * 10⁵

Question 5

Which of the following compounds has the highest pK_a?

A) SiH₄
B) H₂S
C) PH₃
D) HCl

Question 6

Which of the following is the strongest acid?

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

Question 7

Which of the following anions is the strongest base?

A) CH₃COO^-
B) HO^-
C) NH₂^-
D) Cl^-

Question 8

Which of the following compounds is the strongest acid?

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

Question 9

Which of the following compounds is the strongest acid?

A) CH₄
B) CH₃CH₃
C) H₂C=CH₂
D) HCºCH

Question 10

Which of the following is the strongest acid?

A) CH₃NH₂
B) CH₃PH₂
C) CH₃OH
D) CH₃SH

Question 11

Which of the following compounds is the strongest acid?

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

Question 12

Which of the following compounds is the strongest acid?

A) HF
B) H₂O
C) NH₃
D) CH₄

Question 13

Which of the following is easiest to deprotonate?

A) CH₄
B) CH₃CH₃
C) CH₂=CH₂
D) HCºCH

Question 14

Which of the following compounds is the strongest acid?

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

Question 15

Which of the following compounds is the strongest acid?

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

Question 16

Which of the following compounds is the strongest acid?

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

Question 17

Which of the following is the strongest base?

A) NaOH
B) NaCO₃
C) H₂O
D) CH₃OH

Question 18

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 19

Which of the following anions is the strongest base?

A) NH₂^-
B) NH₃
C) CH₃CH=N^-
D) CH₃CºN

Question 20

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]

A) 3.2 * 10⁷
B) -3.2 * 10^-7
C) -3.2 * 10⁷
D) 3.2 * 10^-7

Question 21

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 22

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 23

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

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

Question 24

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 25

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 26

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 27

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 28

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 29

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

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

Question 30

Which of the following compounds has the lowest pK_a?

A) H₂O
B) HBr
C) NH₃
D) CH₄

Question 31

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 32

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 33

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 34

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 35

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

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

Question 36

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 37

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 38

Which of the following compounds has the lowest pK_a?

A) H₂O
B) H₂S
C) H₂Se
D) H₂Te

Question 39

Which of the following compounds has the highest pK_a?

A) NH₃
B) H₂O
C) HCl
D) CH₄

Question 40

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

A) CH₃COOH
B) AlCl₃
C) H₂O
D) CH₃OH

Question 41

What is the approximate pK_a value of acetic acid?

A) -7
B) 5
C) 16
D) 51

Question 42

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

A) CH₃CH₃
B) CH₂=CH₂
C) HCºCH
D) CH₃CH₂OH

Question 43

Which of the following has the highest bond dissociation energy?

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

Question 44

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

A) HBr
B) CH₃COOH
C) CH₃CH₂OH
D) HCºCH

Question 45

Which of the following energy diagrams represents the slowest reaction?

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

Question 46

Which of the following equations is correct?

A) DG $\degree$ = DH $\degree$ - TDS $\degree$
B) DH $\degree$ = DG $\degree$ - TDS $\degree$
C) DG $\degree$ = DH $\degree$ - DS $\degree$
D) DG $\degree$ = DH $\degree$ - DS $\degree$ /T

Question 47

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 48

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 49

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 50

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 51

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 52

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 DG $\degree$ = 0 is 1.
D) DG $\degree$ = DH $\degree$ - TDS $\degree$

Question 53

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

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

Question 54

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 55

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 56

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 57

Under which of the following conditions will a reaction be spontaneous when DH $\degree$ > 0?

A) TDS $\degree$ = 0
B) -TDS $\degree$ > DH $\degree$
C) TDS $\degree$ < 0 $\degree$
D) DG $\degree$ = 0

Question 58

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 59

What is the approximate pK_a value of HCl?

A) -7
B) 5
C) 16
D) 51

Question 60

Which of the following energy diagrams represents the fastest reaction?

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

Question 61

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

Question 62

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

Question 63

Provide a brief explanation, based on features of the molecules, for the following trend in pK_a values?

Question 64

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

Question 65

Provide a brief explanation, based on features of the molecules, for the following trend in pK_a values?

Question 66

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

Question 67

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 68

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

Question 69

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

Question 70

Use curved arrows to show the movement of pairs of electrons in the following reaction between a Lewis acid and a Lewis base, and show the structure of the product.

Question 71

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

Question 72

Use curved arrows to show the movement of pairs of electrons in the following reaction between a Lewis acid and a Lewis base, and show the structure of the product.

Question 73

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

Question 74

Provide a brief explanation, based on features of the molecules, for the following trend in pK_a values?

Question 75

Provide a brief explanation, based on features of the molecules, for the following trend in pK_a values?