Deck 3: Acids and Bases

Question 1

Which of these is not a Lewis acid?

A)AlBr₃
B)BCl₃
C)Ph₃P
D)D⁺
E)All these choices are Lewis acids

Answer 1

Ph₃P

Question 2

Which of the following is a Lewis acid?

A)H₃O⁺
B)BF₃
C)NF₃
D)OH^-
E)More than one of these choices.

Answer 2

More than one of these choices.

Question 3

Which of these is not a Lewis acid?

A)AlCl₃
B)H₃O⁺
C)FeCl₃
D)SO₃
E)C₄H₁₀

Answer 3

C₄H₁₀

Question 4

Which of the following is not a Lewis base?

A)NH₃
B)H^-
C)BF₃
D)H₂O
E)H₃C^-

Question 5

Consider the equilibrium Which are the Bronsted-Lowry bases?

A)PO₄^3- and HPO₄^2-
B)PO₄^3- and OH^-
C)PO₄^3- and H₂O
D)H₂O and OH^-
E)H₂O and HPO₄^2-

Question 6

According to the Lewis definition,a base is a(n)___.

A)proton donor
B)electron pair donor
C)hydroxide ion donor
D)hydrogen ion donor
E)electron pair acceptor

Question 7

This species is a carbon-based Lewis acid:

A)CH₄
B)HCCl₃
C)CH₃⁺
D):CH₃^-
E)·CH₃

Question 8

What is/are the product(s)of the following acid-base mechanism?

A)
B)
C)
D)
E)None of these choices.

Question 9

Which of the following is not a conjugate acid - conjugate base pair (in that order)?

A)H₃PO₄,H₂PO₄^-
B)HBF₄,BF₄^-
C)CH₃CH₂OH,CH₃CH₂O^--
D)H₃O⁺,H₂O
E)HPO₄^2-,H₂PO₄^-

Question 10

What is the conjugate base of ethanol?

A)CH₃CH₂O^-
B)CH₃CH₂^-
C)CH₃CH₂OH₂⁺
D)CH₃CH₃
E)CH₃OCH₃

Question 11

What is/are the product(s)of the following acid-base mechanism?

A)
B)
C)
D)
E)None of these choices.

Question 12

What is/are the product(s)of the following acid-base mechanism?

A)
B)
C)
D)
E)None of these choices.

Question 13

A conjugate base of sulfuric acid is:

A)H₃SO₄⁺
B)SO₃
C)HSO₄^-
D)H₂SO₃
E)HSO₃^-

Question 14

Which pair of species are both bases in the following reaction?

A)H₂O and CN^-
B)H₃O⁺ and H₂O
C)HCN and H₃O⁺
D)HCN and CN^-
E)H₃O⁺ and CN^-

Question 15

What is/are the product(s)of the following acid-base mechanism?

A)
B)
C)
D)
E)None of these choices.

Question 16

Which of the following is not a Bronsted-Lowry acid?

A)H₂O
B)(CH₃)₃N
C)NH₄⁺
D)CH₃CO₂H
E)HC $\equiv$ CH

Question 17

Which of these is not a true statement?

A)All Lewis bases are also Bronsted-Lowry bases.
B)All Lewis acids contain hydrogen.
C)All Bronsted-Lowry acids contain hydrogen.
D)All Lewis acids are electron deficient.
E)According to the Bronsted-Lowry theory,water is both an acid and a base.

Question 18

What is/are the product(s)of the following acid-base mechanism?

A)
B)
C)
D)
E)None of these choices.

Question 19

What is/are the product(s)of the following acid-base mechanism?

A)
B)
C)
D)
E)None of these choices.

Question 20

What is/are the product(s)of the following acid-base mechanism?

A)
B)
C)
D)
E)None of these choices.

Question 21

Which of these phosphorus-based acids is diprotic?

A)
B)
C)
D)
E)

Question 22

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 23

What is the pH of a 1.0 M aqueous solution of CH₃COOH given that its pK_a value is 4.75?

A)0
B)0.0021
C)0.0042
D)2.4
E)2.7

Question 24

In the following reaction which chemical species is acting like a nucleophile?

A)
B)
C)CH₃O^-
D)two of these choices
E)there is no nucleophile in this reaction

Question 25

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 26

Which of the following organic compounds is the strongest acid?

A)C₆H₁₂ pK_a = 52
B)CH₃CH₃ pK_a = 50
C)CH₃CH₂OH pK_a = 18
D)CH₃CO₂H pK_a = 5
E)CF₃CO₂H pK_a = 0

Question 27

In the following reaction,which chemical species is acting like an electrophile?

A)
B)
C)CH₃O^-
D)two of these choices
E)there is no electrophile in this reaction

Question 28

Which of the following organic compounds has the strongest conjugate base?

A)C₆H₁₂ pK_a = 52
B)CH₃CH₃ pK_a = 50
C)CH₃CH₂OH pK_a = 18
D)CH₃CO₂H pK_a = 5
E)CF₃CO₂H pK_a = 0

Question 29

Which of the following correctly lists the compounds in order of decreasing acidity?

A)H₂O > HC $\equiv$ CH > NH₃ > CH₃CH₃
B)HC $\equiv$ H > H₂O > NH₃ > CH₃CH₃
C)CH₃CH₃ > HC $\equiv$ CH > NH₃ > H₂O
D)CH₃CH₃ > HC $\equiv$ CH > H₂O > NH₃
E)H₂O > NH₃ > HC $\equiv$ CH > CH₃CH₃

Question 30

Which is the strongest acid?

A)CH₃CH₂OH
B)CH₃CO₂H
C)HC $\equiv$ CH
D)CH₂=CH₂
E)CH₃CH₃

Question 31

The reaction between which combination of substances below cannot be classified as a Bronsted-Lowry acid-base reaction?

A)CH₃Li + C₂H₅OH
B)H₂SO₄ + CH₃CO₂Na
C)BF₃ + NH₃
D)H₃O⁺ + CH₃NH^-
E)two of these choices

Question 32

For the equilibrium the two substances which are both acids are:

A)H₂O and H₃O⁺
B)CH₃NH₃⁺ and H₂O
C)CH₃NH₃⁺ and CH₃NH₂
D)CH₃NH₃⁺ and H₃O⁺
E)CH₃NH₂ and H₂O

Question 33

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 34

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 35

Rank the following hydrogen atoms from highest to lowest in acidity in the structure shown below.

A)H_a > H_b > H_c > H_d
B)H_a > H_c > H_d > H_b
C)H_c > H_d > H_a > H_b
D)H_d > H_a > H_c > H_b
E)H_c > H_a > H_d > H_b

Question 36

The acidity constant,K_a,differs from the equilibrium constant,K_eq,for the dissociation of the same acid in water at the same temperature and concentration in what way?

A)K_a can be determined experimentally with less accuracy than K_eq.
B)The two terms are identical numerically.
C)K_a is used for strong acids only; K_eq for weak acids.
D)K_a is the reciprocal of K_eq.
E)K_eq = K_a/[H₂O].

Question 37

Hydrogen atom(s)from which position(s)is (are)most likely to be abstracted when the following substance is treated with NaH?

A)1
B)1,5,6
C)1,2
D)3,4,7,8,9,10
E)Hydrogens from all of the positions are equally likely to be abstracted by NaH.

Question 38

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 39

Which of these is not a diprotic acid?

A)H₂S
B)H₂SO₄
C)(COOH)₂
D)H₂PO₄^-
E)All of these choices are diprotic.

Question 40

Which of the following substances has a hydrogen atom with pK_a ≈ 25?

A)CH₃CH₂CH₂CH₂CO₂H
B)CH₃CHCH₂C≡CCH₃
C)CH₃CH₂CH₂C≡CH
D)CH₃CH₂CH₂CH₂CH=CH₂
E)CH₃CH₂CH₂CH₂NH₂

Question 41

The basic species are arranged in decreasing order of basicity in the sequence:

A)F^- > OCH₃^- > NH₂^- > CH₃CH₂^-
B)OCH₃^- > CH₃CH₂^- > NH₂^- > F^-
C)CH₃CH₂^- > NH₂^- > OCH₃^- > F^-
D)NH₂^- > CH₃CH₂^- > F^- > OCH₃^-
E)NH₂^- > OCH₃^- > CH₃CH₂^- > F^-

Question 42

Which is an incorrect statement?

A)RSH compounds are stronger acids than ROH compounds.
B)PH₃ is a weaker base than NH₃.
C)NH₂^- is a stronger base than OH^-.
D)OH^- is a stronger base than OR^-.
E)H^- is a stronger base than OR^-.

Question 43

Which set contains non-equivalent members?

A)enthalpy and heat content
B)endothermic reaction and + $\Delta$ H
C)exothermic reaction and - $\Delta$ H
D)kinetic energy and energy of motion
E)high energy and high stability

Question 44

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 45

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 46

Which one of the following is a true statement?

A)The stronger the acid,the larger is its pK_a.
B)The conjugate base of a strong acid is a strong base.
C)Acid-base reactions always favor the formation of the stronger acid and the stronger base.
D)Strong acids can have negative pK_a values.
E)Hydrogen need not be present in the molecular formula of a Bronsted-Lowry acid.

Question 47

The correct sequence of the ions shown,in order of increasing basicity,is:

A)CH₃CH₂:^- < CH₂=CH:^- < HC $\equiv$ C:^-
B)CH₃CH₂:^- < HC $\equiv$ C:^- < CH₂=CH:^-
C)HC $\equiv$ C:^- < CH₃CH₂:^- < CH₂=CH:^-
D)CH₂=CH:^- < HC $\equiv$ C:^- < CH₃CH₂:^-
E)HC $\equiv$ C:^- < CH₂=CH:^- < CH₃CH₂:^-

Question 48

When proton transfer reactions reach equilibrium,there have been formed

A)the weaker acid and the weaker base.
B)the weaker acid and the stronger base.
C)the stronger acid and the weaker base.
D)the stronger acid and the stronger base.
E)All proton transfers go to completion; they are not equilibrium processes.

Question 49

Which of the acids below would have the strongest conjugate base?

A)CH₃CH₂OH pK_a = 18
B)CH₃CO₂H pK_a = 4.75
C)ClCH₂CO₂H pK_a = 2.81
D)Cl₂CHCO₂H pK_a = 1.29
E)Cl₃CCO₂H pK_a = 0.66

Question 50

Based on the position of the central atom in the periodic chart,we predict that the strongest acid of the following is:

A)H₂O
B)H₂S
C)H₂Se
D)H₂Te
E)All acids are equal in strength.

Question 51

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 52

Why cannot one determine the relative acid strengths of HClO₄ and HNO₃ using aqueous solutions of these acids?

A)The acids are insufficiently soluble for the measurements.
B)A more basic solvent than H₂O must be used.
C)H₂O is too basic a solvent for the distinction to be made.
D)These oxidizing acids cause redox reactions to occur.
E)Actually,the acid strengths can be determined using aqueous solutions.

Question 53

Select the strongest base.

A)OH^-
B)RC $\equiv$ C^-
C)NH₂^-
D)CH₂=CH^-
E)CH₃CH₂^-

Question 54

A group of acids arranged in order of decreasing acidity is: HNO₃ > CH₃COOH > C₆H₅OH > H₂O > HC $\equiv$ CH
What is the arrangement of the conjugate bases of these compounds in decreasing order of basicity?

A)NO₃^- > CH₃COO^- > C₆H₅O^- > OH^- > HC $\equiv$ C^-
B)CH₃COO^- > C₆H₅O^- > NO₃^- > OH^- > HC $\equiv$ C^-
C)C₆H₅O^- > NO₃^- > HC $\equiv$ C^- > OH^- > CH₃COO^-
D)HC $\equiv$ C^- > OH^- > C₆H₅O^- > CH₃COO^- > NO₃^-
E)No prediction of relative base strength is possible.

Question 55

The compounds ethane,ethene,and ethyne exhibit this order of increasing acidity:

A)Ethyne < ethene < ethane
B)Ethene < ethyne < ethane
C)Ethane < ethyne < ethene
D)Ethane < ethene < ethyne
E)Ethene < ethane < ethyne

Question 56

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 57

The compound aniline,C₆H₅NH₂,has weakly basic properties in aqueous solution.In this other solvent,aniline would behave as a strong base.

A)CH₃OH
B)CH₃CH₂OH
C)CF₃CO₂H
D)Liquid NH₃
E)CH₃(CH₂)₄CH₃

Question 58

What prediction can be made of the relative strengths of the conjugate bases of: H₂S,HCl,SiH₄,PH₃?

A)PH₂^- > SiH₃^- > HS^- > Cl^-
B)SiH₃^- > PH₂^- > HS^- > Cl^-
C)Cl^- > HS^- > PH₂^- > SiH₃^-
D)HS^- > Cl^- > SiH₃^- > PH₂^-
E)Cl^- > PH₂^- > SiH₃^- > HS^-

Question 59

For the simple hydrides,MH_n,pK_a values decrease in the order:

A)CH₄ > NH₃ > H₂O > H₂S > HBr
B)HBr > H₂S > H₂O > NH₃ > CH₄
C)HBr > H₂O > NH₃ > H₂S > CH₄
D)NH₃ > H₂S > CH₄ > H₂O > HBr
E)H₂S > H₂O > HBr > NH₃ > CH₄

Question 60

An acid,HA,has the following thermodynamic values for its dissociation in water at 27 ºC: $\Delta$ H = -8.0 kJ mol^-1; $\Delta$ S = -70 J K^-1mol^-1.The $\Delta$ G for the process is:

A)+29 kJ mol^-1
B)+13 kJ mol^-1
C)-6.1 kJ mol^-1
D)-13 kJ mol^-1
E)-29 kJ mol^-1

Question 61

For the following acid-base reaction,which statement is true taking $\Delta$ S into consideration?

A)The reaction is an exothermic reaction and $\Delta$ S is positive.
B)The reaction is an exothermic reaction and $\Delta$ S is approximately zero.
C)The reaction is an endothermic reaction and $\Delta$ S is positive.
D)The reaction is an endothermic reaction and $\Delta$ S is approximately zero.
E)None of these choices.

Question 62

Which is the weakest acid?

A)CH₃CH₂CH₂CH₂CHFCO₂H
B)CH₃CHCH₂CH₂CH₂CH₂OH
C)CH₃CH₂CH₂CH₂CH₂SO₃H
D)CH₃CH₂CH₂CH₂CH=CH₂
E)CH₃CH₂CH₂CH₂NH₂

Question 63

For the following acid/base reaction which statement is true taking $\Delta$ S into consideration?

A)The reaction is an exothermic reaction and $\Delta$ S is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ S is negative.
C)The reaction is an exothermic reaction and $\Delta$ S is negative.
D)The reaction is an exothermic reaction and $\Delta$ S is positive.
E)None of these choices.

Question 64

For the following acid / base reaction which statement is true taking $\Delta$ H into consideration?

A)The reaction is an exothermic reaction and $\Delta$ H is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ H is negative.
C)The reaction is an exothermic reaction and $\Delta$ H is negative.
D)The reaction is an exothermic reaction and $\Delta$ H is positive.
E)None of these choices.

Question 65

For the following acid/base reaction which statement is true taking $\Delta$ S into consideration?

A)The reaction is an endothermic reaction and $\Delta$ S is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ S is negative.
C)The reaction is an exothermic reaction and $\Delta$ S is negative.
D)The reaction is an exothermic reaction and $\Delta$ S is approximately zero.
E)None of these choices.

Question 66

Rank the bold-faced hydrogens for the following compounds from most acidic to least acidic.

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

Question 67

For the following acid-base reaction,which statement is true taking $\Delta$ S into consideration?

A)The reaction is an exothermic reaction and $\Delta$ S is positive.
B)The reaction is an exothermic reaction and $\Delta$ S is negative.
C)The reaction is an endothermic reaction and $\Delta$ S is positive.
D)The reaction is an endothermic reaction and $\Delta$ S is approximately zero.
E)None of these choices.

Question 68

For the following acid / base reaction which statement is true taking $\Delta$ S into consideration?

A)The reaction is an endothermic reaction and $\Delta$ S is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ S is negative.
C)The reaction is an exothermic reaction and $\Delta$ S is negative.
D)The reaction is an exothermic reaction and $\Delta$ S is approximately zero.
E)None of these choices.

Question 69

For the following acid / base reaction which statement is true taking $\Delta$ H into consideration?

A)The reaction is an exothermic reaction and $\Delta$ H is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ H is negative.
C)The reaction is an exothermic reaction and $\Delta$ H is negative.
D)The reaction is an exothermic reaction and $\Delta$ H is positive.
E)None of these choices.

Question 70

Which is the strongest acid?

A)CH₂ClCH₂CH₂CH₂CH₂CO₂H
B)CH₃CHBrCH₂CH₂CH₂CO₂H
C)CH₃CH₂CH₂CBr₂CH₂CO₂H
D)CH₃CH₂CH₂CHFCH₂CO₂H
E)CH₃CH₂CH₂CF₂CH₂CO₂H

Question 71

For the following acid/base reaction which statement is true taking $\Delta$ S into consideration?

A)" $\Delta$ G is negative and $\Delta$ S is approximately zero"
B)" $\Delta$ G is negative and $\Delta$ S is negative"
C)" $\Delta$ G is positive and $\Delta$ S is positive"
D)" $\Delta$ G is negative and $\Delta$ S is positive"
E)"None of these choices."

Question 72

For the following acid/base reaction which statement is true taking $\Delta$ S into consideration?

A)The reaction is an exothermic reaction and $\Delta$ S is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ S is negative.
C)The reaction is an exothermic reaction and $\Delta$ S is negative.
D)The reaction is an exothermic reaction and $\Delta$ S is positive.
E)None of these choices.

Question 73

For the following acid-base reaction,which statement is true taking $\Delta$ H into consideration?

A)The reaction is an exothermic reaction and $\Delta$ H is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ H is negative.
C)The reaction is an endothermic reaction and $\Delta$ H is positive.
D)The reaction is an exothermic reaction and $\Delta$ H is negative.
E)None of these choices.

Question 74

For the following acid-base reaction,which statement is true taking $\Delta$ S into consideration?

A)" $\Delta$ G is negative and $\Delta$ S is approximately zero"
B)" $\Delta$ G is positive and $\Delta$ S is approximately zero"
C)" $\Delta$ G is positive and $\Delta$ S is negative"
D)" $\Delta$ G is negative and $\Delta$ S is positive"
E)"None of these choices."

Question 75

For the following acid-base reaction,which statement is true taking $\Delta$ H into consideration?

A)The reaction is an exothermic reaction and $\Delta$ H is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ H is negative.
C)The reaction is an exothermic reaction and $\Delta$ H is negative.
D)The reaction is an endothermic reaction and $\Delta$ H is positive.
E)None of these choices.

Question 76

For the following acid/base reaction which statement is true taking $\Delta$ S into consideration?

A)The reaction is an exothermic reaction and $\Delta$ S is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ S is negative.
C)The reaction is an exothermic reaction and $\Delta$ S is negative.
D)The reaction is an exothermic reaction and $\Delta$ S is positive.
E)None of these choices.

Question 77

Which is the strongest acid?

A)CH₃CH₂CH₂CH₂CHFCO₂H
B)CH₃CHBrCH₂CH₂CH₂CO₂H
C)CH₃CH₂CH₂CHClCH₂CO₂H
D)CH₃CH₂CH₂CHFCH₂CO₂H
E)CH₃CH₂CH₂CHICH₂CO₂H

Question 78

Which of the following is an untrue statement?

A)The % dissociation of a weak acid increases with increasing dilution of the acid solution.
B)The stronger an acid,the weaker its conjugate base.
C)The larger the value of K_a for an acid,the smaller the value of its pK_a.
D)Comparison of the acidity of strong acids in solution requires the use of a solvent less basic than water.
E)The stronger the acid,the more positive the value of $\Delta$ Gº for the dissociation.

Question 79

For the following acid/base reaction which statement is true taking $\Delta$ S into consideration?

A)" $\Delta$ G is negative and $\Delta$ S is approximately zero"
B)" $\Delta$ G is negative and $\Delta$ S is negative"
C)" $\Delta$ G is positive and $\Delta$ S is positive"
D)" $\Delta$ G is negative and $\Delta$ S is positive"
E)"None of these choices."

Question 80

For the following acid / base reaction which statement is true taking $\Delta$ H into consideration?

A)The reaction is an exothermic reaction and $\Delta$ H is approximately zero.
B)The reaction is an endothermic reaction and $\Delta$ H is negative.
C)The reaction is an exothermic reaction and $\Delta$ H is negative.
D)The reaction is an exothermic reaction and $\Delta$ H is positive.
E)None of these choices.