Deck 2: Polar Covalent Bonds: Acids and Bases

Question 1

Instructions: Indole is pleasant smelling in highly dilute solutions and has been used in perfumery.Use the structure of indole,below,to answer the following question(s).

Refer to instructions.Indole can function as a Brønsted-Lowry acid in the presence of strong bases.Formulate a reaction,using a generic base (:B^-),showing electron flow with arrows,that demonstrates this reactivity of indole.

Answer 1

Question 2

The following shows an intermediate used in a Grignard synthesis.Which atom will inductively donate electrons in this species?

A)C
B)Br
C)Mg
D)H
E)both b and c

Answer 2

Mg

Question 3

Circle the Lewis bases in the group of compounds below.

Answer 3

Question 4

What is the formal charge on the nitrogen atom indicated with the arrow in the following compound?

A)0
B)-1
C)+1
D)-2
E)+2

Question 5

Explain why phenol has a lower pK_a than ethanol.

Question 6

Instructions: Indole is pleasant smelling in highly dilute solutions and has been used in perfumery.Use the structure of indole,below,to answer the following question(s).

Refer to instructions.Indole can function as a Lewis base in the presence of strong acid.Formulate a reaction,using a generic acid (HA),showing electron flow with arrows,that demonstrates this reactivity of indole.

Question 7

Instructions: Refer to the following equation to answer the question(s)below.


Refer to instructions.The strongest Brønsted-Lowry base in the equation is indicated by letter _____.

A)A
B)B
C)C
D)D

Question 8

Which of the following molecules has a dipole moment?

A)
B)
C)
D)

Question 9

Instructions: Label the acid and base in each reaction below.
Label:

Question 10

Instructions: Consider the species below to answer the following question.

Refer to instructions.Which of the following would be common to all?

A)Lewis acids
B)Lewis bases
C)Lewis acids or bases
D)Neither Lewis acids nor bases

Question 11

Of the bonds found in
Which is the most polar?

A)C-F
B)O-H
C)C-H
D)C-O

Question 12

Instructions: Refer to the following equation to answer the question(s)below.

Refer to instructions.Will this reaction take place as written in the forward direction? Explain.

Question 13

The condensed structure for dimethyl ether looks symmetrical.However,dimethyl ether has a dipole moment.Draw a structure that explains this and indicate the expected direction of the molecular dipole moment.

Question 14

Which of the following statements is not true regarding resonance structures?

A)All resonance structures must have the same number of electrons
B)All resonance structures must differ in the hybridization of atoms.
C)All resonance structures must have the same arrangement of atoms
D)All resonance structures must be valid Lewis structures

Question 15

Instructions: Refer to the following equation to answer the question(s)below.


Refer to instructions.The strongest Brønsted-Lowry acid in the equation is indicated by letter _____.

A)A
B)B
C)C
D)D

Question 16

Draw two resonance structures for the species below.

Question 17

Among the following compounds which can function only as a Brønsted-Lowry base?

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

Question 18

Consider the structure of acetic acid shown below.
In the electrostatic potential map of acetic acid,in which of the following bonds would the terminal atom appear as the deepest shade of red?

A)C=O
B)C-H
C)C-C
D)O-H

Question 19

Which of the following molecules would exhibit the largest dipole moment?

A)CH₃CH₃
B)CH₃CH₂F
C)CH₃CH₂Cl
D)CH₃CH₂Br

Question 20

Instructions: Consider the reaction below to answer the following question.

Refer to instructions.Using the curved arrow formalism,show the flow of electrons for this reaction.

Question 21

Draw a Lewis structure for each of the following.

Question 22

Instructions: Consider the molecules below to answer the following question.

Refer to instructions.Which of the following is an accurate description of the noncovalent interactions between like molecules?

A)Only 1 exhibits hydrogen bonding.
B)Only 2 exhibits hydrogen bonding.
C)Only 3 exhibits hydrogen bonding.
D)Only 1 and 2 exhibit hydrogen bonding.
E)All of these exhibit hydrogen bonding.

Question 23

Write an equation for the reaction of boron trifluoride,an important reagent in organic chemistry,with trimethylamine.Represent the movement of electrons with a curved arrow,and show the formal charges on the atoms in the product.

Question 24

Which of the following exhibits only dispersion forces?

A)only a
B)only b
C)only c
D)only d
E)all except b

Question 25

Write an equation for the reaction of the alkaloid ephedrine with a proton,showing the structure of its conjugate base.

Question 26

Guanidine is a fairly strong amine base that is attached to the amino acid arginine.Draw three resonance forms for the conjugate acid of guanidine.

Question 27

Identify the reactants and product in the reaction below as acids or bases and specify whether they are Lewis and/or Brønsted-Lowry.

Question 28

Draw two resonance forms for the cyclopentadienyl radical.

Question 29

Rank the following in order of decreasing importance as a contributing resonance structure to the molecular structure of acetone,CH₃COCH₃ (more important > less important).

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

Question 30

The visual pigment in animal cells consists of an isomer of retinal linked to the protein opsin,as shown below.Write an alternative resonance form for this species that shows the positive charge situated on the starred carbon instead of the nitrogen atom and include the curved arrows to show the electron flow.

Question 31

Complete this acid-base reaction,and label the acid,base,conjugate base,and conjugate acid.

Question 32

Use the curved arrow method to show the electron movement,and label the acid,base,conjugate acid,and conjugate base.

Question 33

In aromatic nitration reactions,nitric acid (HNO₃)is used in conjunction with the stronger acid,sulfuric acid,H₂SO₄,to form an intermediate.Which of the following could be the formula for this intermediate?

A)NO₃^-
B)H₃SO₄⁺
C)H₂NO₃⁺
D)HNO₂

Question 34

Draw the conjugate base of each species.

Question 35

Which is the strongest base (pK_a values given for conjugate acid)?

A)NH₃ (pK_a = 9.2)
B)CH₃O^- (pK_a = 16)
C)
(pK_a = -6.5)
D)CH₃CO₂^- (pK_a = 4.7)
E)H^- (pK_a = 35)