Deck 2: Acids and Bases

Question 1

Which is the conjugate acid in the following reaction?

A)I
B)II
C)III
D)IV

Answer 1

IV

Question 2

Which of the following species is the conjugate base of the hydronium ion,H₃O⁺?

A)H₃O
B)H₂O^-
C)H₂O
D)HO^-

Answer 2

H₂O

Question 3

Which is the conjugate acid in the following reaction?

A)I
B)II
C)III
D)IV

Answer 3

III

Question 4

Which of the following compounds is the strongest acid?

A)I
B)II
C)III
D)IV

Question 5

Which of the following species cannot act as both a Brønsted-Lowry acid and base?

A)HCO₃^-
B)HSO₄^-
C)HO^-
D)H₂PO₄^-

Question 6

Which of the following species is the conjugate base of methanol,CH₃OH?

A)CH₃OH₂⁺
B)CH₃O^-
C)CH₃^-
D)CH₄

Question 7

Which of the following species is the strongest base?

A)HO^-
B)H₂N^-
C)CH₃COO^-
D)Cl^-

Question 8

Which of the following statements about acid strength is true?

A)The stronger the acid,the further the equilibrium lies to the left.
B)The stronger the acid,the smaller the K_a.
C)The stronger the acid,the larger the pK_a.
D)The stronger the acid,the smaller the pK_a.

Question 9

Which of the following statements is a correct definition for a Brønsted-Lowry acid?

A)Proton acceptor
B)Electron pair donor
C)Electron pair acceptor
D)Proton donor

Question 10

Which of the following statements about a Brønsted-Lowry base is true?

A)The net charge may be zero,positive,or negative.
B)All Brønsted-Lowry bases contain a lone pair of electrons or a π bond.
C)All Brønsted-Lowry bases contain a proton.
D)The net charge may be zero or positive.

Question 11

Which is the conjugate base in the following reaction?

A)I
B)II
C)III
D)IV

Question 12

Which of the following species is not a Brønsted-Lowry base?

A)BF₃
B)NH₃
C)H₂O
D)PO₄^3-

Question 13

Which is the conjugate base in the following reaction?

A)I
B)II
C)III
D)IV

Question 14

Which of the following compounds is the strongest acid?

A)CH₃OH
B)BrCH₂OH
C)CH₃NH₂
D)CH₃Cl

Question 15

Which of the following species is the conjugate acid of ammonia,NH₃?

A)H₄N
B)H₃N⁺
C)H₂N^-
D)H₄N⁺

Question 16

Which of the following compounds is both a Brønsted-Lowry acid and base?

A)I,II
B)I,III
C)II,IV
D)I,IV

Question 17

Which of the following ranks the compounds in order of increasing basicity,putting the least basic first?

A)CH₃NH₂ < CH₃OH < CH₄
B)CH₃OH < CH₃NH₂ < CH₄
C)CH₄ < CH₃NH₂ < CH₃OH
D)CH₄ < CH₃OH < CH₃NH₂

Question 18

Which of the following compounds is the weakest acid?

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

Question 19

Which of the following compounds is the weakest acid?

A)H₂S
B)PH₃
C)HCl
D)SiH₄

Question 20

Which of the following statements about Brønsted-Lowry acids and bases is true?

A)Loss of a proton from a base forms its conjugate acid.
B)Loss of a proton from an acid forms its conjugate base.
C)Gain of a proton by an acid forms its conjugate base.
D)Brønsted-Lowry acid-base reactions always result in the transfer of a proton from a base to an acid.

Question 21

Rank the following compounds in order of increasing acidity,putting the least acidic first.

A)III < I < IV < II
B)III < IV < I < II
C)II < I < IV < III
D)III < I < II < IV

Question 22

Which of the following statements about Lewis bases is true?

A)Lewis bases are electron pair acceptors.
B)Lewis bases are electron pair donors.
C)Lewis bases are proton donors.
D)Lewis bases are proton acceptors.

Question 23

Which of the following concepts can be used to explain the difference in acidity between ethanol (CH₃CH₂OH)and 2-fluoroethanol (FCH₂CH₂OH)?

A)Size
B)Inductive effect
C)Resonance
D)Hybridization

Question 24

What is the direction of equilibrium when acetylene (C₂H₂)reacts with ethoxide (CH₃CH₂O^-)in an acid-base reaction?

A)Left
B)Right
C)Neither
D)Cannot be determined

Question 25

What is the direction of equilibrium when acetylene (C₂H₂)reacts with H₂N^- in an acid-base reaction?

A)Left
B)Right
C)Neither
D)Cannot be determined

Question 26

Rank the following compounds in order of decreasing acidity,putting the most acidic first.

A)IV > II > III > I
B)III > II > IV > I
C)I > II > IV > III
D)III > IV > II > I

Question 27

Rank the following conjugate bases in order of decreasing basicity,putting the most basic first.

A)II > I > III
B)I > II > III
C)III > I > II
D)III > II > I

Question 28

Which of the following concepts can be used to explain the difference in acidity between acetylene (C₂H₂)and ethylene (C₂H₄)?

A)Size
B)Resonance
C)Inductive effect
D)Hybridization

Question 29

Rank the following compounds in order of increasing acidity,putting the least acidic first.

A)I < IV < III < II
B)I < III < IV < II
C)II < III < IV < I
D)II < IV < III < I

Question 30

Which of the following concepts can be used to explain the difference in acidity between acetic acid (CH₃COOH)and ethanol (CH₃CH₂OH)?

A)Hybridization
B)Electronegativity
C)Resonance
D)Size

Question 31

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

A)CH₃OH
B)H₂O
C)CH₃COOH
D)BF₃

Question 32

Consider the following molecule with protons labeled,I-III.Rank these protons in order of decreasing acidity,putting the most acidic first.

A)I > II > III
B)I > III > II
C)III > II > I
D)III > I > II

Question 33

Which of the following is the strongest base?

A)CH₃COCH₃
B)CH₃COOH
C)NH₃
D)H₂O

Question 34

Rank the following conjugate bases in order of increasing basicity,putting the least basic first.

A)II < I < III
B)II < III < I
C)I < II < III
D)I < III < II

Question 35

Which of the following compounds has the lowest pK_a?

A)H₂O
B)H₂S
C)NH₃
D)CH₄

Question 36

Which of the following statements explains why H₂O is a stronger acid than CH₄?

A)H₂O can form hydrogen bonds while CH₄ cannot.
B)H₂O forms a less stable conjugate base,HO^-.
C)CH₄ forms a more stable conjugate base,CH₃^-.
D)H₂O forms a more stable conjugate base,HO^-.

Question 37

Which of the following statements explain why HBr is a stronger acid than HF?

A)Br^- is more stable than F^- because Br^- is larger than F^-.
B)Br^- is less stable than F^- because Br^- is larger than F^-.
C)Br^- is more stable than F^- because Br^- is less electronegative than F^-.
D)Br^- is less stable than F^- because Br^- is less electronegative than F^-.

Question 38

Which of the following statements about Lewis acids is true?

A)Lewis acids are proton donors.
B)Lewis acids are proton acceptors.
C)Lewis acids are electron pair donors.
D)Lewis acids are electron pair acceptors.

Question 39

Rank the following compounds in order of decreasing acidity,putting the most acidic first.

A)IV > II > III > I
B)IV > III > II > I
C)III > IV > II > I
D)III > IV > I > II

Question 40

Rank the following compounds in order of decreasing acidity,putting the most acidic first.

A)I > II > III
B)III > II > I
C)II > III > I
D)III > I > II

Question 41

What is the correct classification of the following compound? CH₃-O-CH₃

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

Question 42

Which of the following compounds is not a Lewis acid?

A)AlCl₃
B)HCl
C)H₂O
D)CBr₄

Question 43

What is the nucleophilic site in the following compounds?

A)I = Hydrogen; II = π electrons in bond; III = nitrogen.
B)I = Oxygen; II = carbon; III = nitrogen.
C)I = Hydrogen; II = carbon; III = carbon.
D)I = Oxygen; II = π electrons in bond; III = nitrogen.

Question 44

Which of the following will proceed as written?

A)CH₃ONa + HCl → CH₃OH + NaCl
B)CH₃OH + NaCl → NaOEt + HCl
C)CH₃OH + H₂O → CH₃O^- + H₃O+
D)CH₃OH + NH₃ → CH₃O^- + NH₄^±

Question 45

Consider the following structures I-IV.Which two species represent constitutional isomers?

A)I and II
B)I and III
C)I and IV
D)II and IV

Question 46

Identify the Lewis acid in the following reaction.

A)I
B)II
C)III
D)IV

Question 47

What is the role of methylchloride (CH₃Cl)in the following reaction?

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

Question 48

Identify the acid/conjugate acid (in that order)in the following reaction:

A)I,III
B)I,IV
C)II,III
D)II,IV

Question 49

Identify the Lewis base in the following reaction.

A)I
B)II
C)III
D)IV

Question 50

Identify the base/conjugate base (in that order)in the following reaction:

A)I,III
B)I,IV
C)II,III
D)II,IV

Question 51

Consider the following structures I-IV.Which two species represent resonance structures?

A)I and II
B)I and III
C)I and IV
D)II and IV

Question 52

What is the conjugate base of HSO₄^-? SO₄^2- H₂SO₄ SO₃ H₂O
I II III IV

A)I
B)II
C)III
D)IV

Question 53

Consider the following structures I-IV.Which two species represent a conjugate acid-base pair?

A)I and II
B)I and III
C)I and IV
D)II and III

Question 54

What are the products of the following proton transfer reaction?

A)I
B)II
C)III
D)IV

Question 55

What is the electrophilic site in the following compounds?

A)I = Carbon; II = carbon; III = boron.
B)I = Chlorine; II = carbon; III = boron.
C)I = Carbon; II = oxygen; III = boron.
D)I = Carbon; II = carbon; III = fluorine.

Question 56

Which of the following ranks the compounds in order of increasing acidity,putting the least acidic first?

A)CH₄ < H₂O < NH₃
B)H₂O < NH₃ < CH₄
C)NH₃ < CH₄ < H₂O
D)CH₄ < NH₃ < H₂O

Question 57

Which of the following species can be both Lewis acid and Lewis base?

A)I,III,IV
B)I,II,IV
C)II,III,IV
D)I,II,III

Question 58

What is the correct rank of the following compounds in order of increasing acidity?

A)I > II > III > IV
B)IV > III > II > I
C)IV > I > II > III
D)III > I > IV > II

Question 59

Which of the following would have the lowest pKa?

A)ClCH₂CH₂CH₂CH₂COOH
B)CH₃CHClCH₂CH₂COOH
C)CH₃CH₂CHClCH₂COOH
D)CH₃CH₂CH₂CHClCOOH