Deck 5: Organic Reaction Mechanisms

Question 1

Which of the following has the biggest contribution to a significant resonance form?

A)the most atoms with full octets
B)the fewest number of formal charges
C)the largest spread of like formal charges
D)the negative formal charges on the most electronegative atoms

Answer 1

the most atoms with full octets

Question 2

What do curved arrows in organic reaction mechanisms represent?

A)the flow of electrons in a reaction
B)the flow of atoms in a reaction
C)the breaking of bonds in a reaction
D)the flow of positive charge in a reaction

Answer 2

the flow of electrons in a reaction

Question 3

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,what is the formal charge of the oxygen atom at B?

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

Answer 3

-1

Question 4

What is the formal charge of the nitrogen atom in the structure shown below?

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

Question 5

Which of the following best describes carbanions?

A)They are Lewis acids and electrophilic.
B)They are Lewis bases and electrophilic.
C)They are Lewis acids and nucleophilic.
D)They are Lewis bases and nucleophilic.

Question 6

Which of the following best describes an intramolecular reaction?

A)Only a single molecule is involved.
B)Only a single functional group is involved.
C)More than one molecule is involved.
D)More than one curved arrow is involved.

Question 7

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,what is the formal charge of the nitrogen atom at A?

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

Question 8

how many lone pair electrons are around the negatively charged carbon atom shown below?

A)0
B)1
C)2
D)3

Question 9

Which of the following arrows represents resonance between two structures?

A)
B)
C)
D)

Question 10

Which of the following is NOT a resonance structure of the amide bond shown below?

A)
B)
C)
D)

Question 11

What is the formal charge around the oxygen atom shown below?

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

Question 12

what is the formal charge of each of the nitrogen atoms in the azide functional group shown below.

A)a = 0,b = +1,c = 0
B)a = +1,b = -1,c = 0
C)a = 0,b = +1,c = -1
D)a = -1,b = +1,c = -1

Question 13

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,how many lone pairs of electrons can be found on the nitrogen atom at A?

A)0
B)1
C)2
D)3

Question 14

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,which of the following best describes the resonance states I and II?

A)I is more stable than II because the formal negative charge is on a more electronegative atom.
B)I is more stable than II because all the atoms follow the octet rule.
C)II is more stable than I because the formal negative charge is on a more electronegative atom.
D)II is more stable than I because all the atoms follow the octet rule.

Question 15

Which of the following best describes an atom with an unpaired electron?

A)anion
B)cation
C)radical
D)nucleophile

Question 16

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,what is the formal charge of the nitrogen atom at C?

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

Question 17

Which of the following best describes carbocations?

A)They are electrophilic and electron deficient.
B)They are electrophilic and electron rich.
C)They are nucleophilic and electron deficient.
D)They are nucleophilic and electron rich.

Question 18

What is the formal charge of the nitrogen atom shown below?

A)-3
B)0
C)+1
D)+5

Question 19

Which of the following best describes the resonance forms of an amide bond shown below?

A)A is the largest contributor;B is the smallest contributor.
B)A is the largest contributor;C is the smallest contributor.
C)B is the largest contributor;C is the smallest contributor.
D)C is the largest contributor;B is the smallest contributor.

Question 20

Which of the following represents the correct arrow flow in the reaction shown below?

A)
B)
C)
D)

Question 21

Curved arrows in reaction mechanism go from a positive site to a negative site.

Question 22

Intramolecular reactions involve only a single reactant.

Question 23

Which of the following compounds is NOT a resonance form of the species shown below?

A)
B)
C)
D)

Question 24

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,how many lone pairs of electrons can be found on the nitrogen atom at F?

A)0
B)1
C)2
D)3

Question 25

What is the product or products of the following arrow pushing?

A)
B)
C)
D)

Question 26

Given the Lewis structure shown below,what are the formal charges of the sulfur and oxygen atoms?

A)sulfur = +1,oxygen = -1
B)sulfur = 0,oxygen = 0
C)sulfur = -1 oxygen = +1
D)sulfur = 0 oxygen = -1

Question 27

Both ð and ó bonds can be involved in resonance.

Question 28

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,how many lone pairs of electrons can be found on the nitrogen atom at E?

A)0
B)1
C)2
D)3

Question 29

What is the product or products of the following arrow pushing?

A)
B)
C)
D)

Question 30

Curved arrows in reaction mechanism show the flow of atoms.

Question 31

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,how many lone pairs of electrons can be found on the oxygen atom at B?

A)0
B)1
C)2
D)3

Question 32

Given the following Lewis structure,how many lone pairs are expected to be around the sulfur and oxygen atom?

A)sulfur = 2,oxygen = 2
B)sulfur = 1,oxygen = 2
C)sulfur = 2 oxygen = 3
D)sulfur = 1 oxygen = 3

Question 33

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,how many lone pairs of electrons can be found on the nitrogen atom at C?

A)0
B)1
C)2
D)3

Question 34

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,how many lone pairs of electrons can be found on the carbon atom at D?

A)0
B)1
C)2
D)3

Question 35

Which of the following is the most important guideline when assessing the quality of resonance forms?

A)the fewest number of formal charges
B)negative charges located on the most electronegative atoms
C)positive charges located on the least electronegative atoms
D)the most atoms with the full octets

Question 36

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,what is the formal charge of the nitrogen atom at E?

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

Question 37

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,what is the formal charge of the carbon atom at D?

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

Question 38

Figure 1
Shown below is the structure of caffeine in the centre and two different resonance states I and II with lone pairs and formal charges omitted.
Referring to Figure 1,what is the formal charge of the nitrogen atom at F?

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

Question 39

Different curved arrow shapes exist for one and two electron movement.

Question 40

Curved mechanism arrows flow from nucleophile to electrophile.

Question 41

Curved arrows always represent the flow of electron pairs.

Question 42

Curved arrows in reaction mechanism show both bond breaking and bond forming.

Question 43

Atoms with full octets have more of an influence on the contribution of a resonance form than the amount of formal charges.

Question 44

Resonance structures are in equilibrium with each other.

Question 45

Resonance structures require at least two neighboring atoms with p-orbitals.

Question 46

A carbocation contains a p orbital capable of receiving electrons to form a new bond.

Question 47

A resonance form is a blend of all resonance forms at the same time.

Question 48

All resonance forms contribute equally to a resonance hybrid.

Question 49

Structures with unpaired electrons are also referred to as radicals.

Question 50

When evaluating resonance forms,an optimal structure is one that places positive formal charges on atoms with high electronegativity.

Question 51

An oxygen atom with two ó bonds,one ð bond,and a lone pair of electrons has a formal charge of -1.

Question 52

All atoms with positive charge can receive electrons through bond formation.

Question 53

Delocalization of electrons occurs over p orbitals that are parallel AND perpendicular to each other.

Question 54

Resonance has no effect on the stability of a structure.

Question 55

A ð bond between two atoms with different electronegativities can undergo resonance.

Question 56

Atoms with arrows pointing away from them increase in negative charge.

Question 57

Structures in resonance exist with distinct chemical structures.

Question 58

A structure that contains an atom with an unpaired electron is called a(n)_______________ ,

Question 59

Atoms with full octets have no influence on the contribution of individual resonance forms.

Question 60

All resonance forms have equal contribution to a resonance hybrid.

Question 61

The formal charge of a sulfur atom with one ó bond,one ð bond,and two lone pairs of electrons is _______________.

Question 62

A reaction with curved arrows moving between two different molecules is an example of a(n)_______________ reaction.

Question 63

Which of the following compounds would you expect to have greater resonance stabilization.Use curved arrows and resonance structures to demonstrate why.

Question 64

Insert in all formal charges of the product from the arrow pushing shown below.Add all lone pairs to the product.

Question 65

Draw all the resonance structures of the p-dimethylamino pyridinium ion shown below.Use curved arrows to transition from one resonance form to another.

Question 66

Draw the product(s)of the following arrow pushing shown below.Include all formal charges.

Question 67

A curved arrow pointing to an atom in a reaction mechanism _______________ its charge integer.

Question 68

Insert curved arrows in 7-dehydrocholesterol to show how it becomes Previtamin D_.

Question 69

The formal charge of a Boron atom with four ó bonds is _______________.

Question 70

Draw curved arrows to show electron flow in the following transformation.

Question 71

Different resonance forms of a structure are separated by a(n)_______________ arrow

Question 72

The movement of a single electron in a reaction mechanism involves the use of a(n)_______________ arrow

Question 73

Using curved arrows,show the flow of electrons to obtain the greatest resonance contributor to the following compound,and state why this is the greatest resonance contributor.

Question 74

A highly contributing resonance structure places positive formal charges on the _______________ electronegative atom.

Question 75

Use curved arrows to show the electron flow in the following transformation.

Question 76

Curved arrows show the movement of _______________ in reaction mechanisms.

Question 77

Curved arrows within the same structure are an example of a(n)_______________ reaction.