Deck 18: Structure Determination 2: Nuclear Magnetic Resonance Spectroscopy and Mass Spectrometry

Question 1

How many distinct signals are in the ¹³C NMR of the following compound?

A)Four
B)Five
C)Six
D)Seven
E)Eight

Answer 1

Six

Question 2

Which will produce the largest coupling constant?

A)H_A coupling to H_B
B)H_A coupling to H_C
C)H_B coupling to H_C
D)H_C coupling to H_D
E)H_D coupling to H_E

Answer 2

H_B coupling to H_C

Question 3

Which hydrogen type has the smallest integration value?

A)H_A
B)H_B
C)H_C
D)H_D
E)H_E

Answer 3

H_A

Question 4

How many chemically distinct hydrogen atoms are in the following molecule?

A)Two types
B)Three types
C)Four types
D)Five types
E)Six types

Question 5

What apparent splitting pattern would not be found in the ¹H NMR spectrum or the following molecule?

A)Singlet
B)Doublet
C)Triplet
D)Quartet
E)Quintet

Question 6

Which molecule has a triplet of doublets in its ¹H NMR spectrum?

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

Question 7

H_A splits the ¹H NMR signal for H_B by 7.4 Hz.By how much does H_B split the ¹H NMR signal for H_A?

A)0 Hz
B)3.7 Hz
C)7.4 Hz
D)14.8 Hz
E)Not enough information to answer

Question 8

Which compound has four distinct signals in its ¹³C NMR spectrum?

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

Question 9

How many chemically distinct hydrogen atoms are in the following molecule?

A)Two types
B)Three types
C)Four types
D)Five types
E)Six types

Question 10

Which hydrogen type has the greatest integration value?

A)H_A
B)H_B
C)H_C
D)H_D
E)H_E

Question 11

Which molecule does not have a doublet of doublets in its ¹H NMR spectrum?

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

Question 12

What is the expected splitting pattern for the indicated hydrogen?

A)Singlet
B)Doublet
C)Triplet
D)Quartet
E)Quintet

Question 13

Which molecule will have the greatest coupling constant between H_A and H_B?

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

Question 14

Which hydrogen atom has the greatest chemical shift?

A)H_A
B)H_B
C)H_C
D)H_D
E)H_E

Question 15

What is the expected splitting pattern for the indicated hydrogen?

A)Singlet
B)Doublet
C)Triplet
D)Quartet
E)Quintet

Question 16

Which of the following molecules would have a quartet at 3.5 ppm?

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

Question 17

Which hydrogen atom has the greatest chemical shift?

A)H_A
B)H_B
C)H_C
D)H_D
E)H_E

Question 18

What is the relative ratio of hydrogens in the following molecule?

A)3:3:1:2:2:2:1:3:3
B)6:1:2:1
C)6:1:2:2:2:1:6
D)12:2:2:2:2
E)None (a-d) give the correct relative ratio of hydrogens.

Question 19

Which of the following molecules would have a singlet at 2.1 ppm?

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

Question 20

How many chemically distinct hydrogen atoms are in the following molecule?

A)Four types
B)Five types
C)Six types
D)Seven types
E)Eight types

Question 21

Which compound would produce the ¹H NMR spectrum below?

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

Question 22

Which compound would produce the ¹H NMR spectrum below?

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

Question 23

Which proton in the following molecule has the greatest chemical shift?

Question 24

Which proton in the following molecule has the greatest chemical shift?

Question 25

Which type of atom is likely present in the molecule responsible for the following mass spectrum?

A)N
B)F
C)Cl
D)Br
E)I

Question 26

What is the expected splitting pattern for the indicated hydrogen?

Question 27

Which hydrogen in the following molecule has the greatest integration value?

Question 28

The mass spectrum for an unknown molecule has an M ⁺ peak with a relative intensity of 50 and an M + 1 peak with a relative intensity of 1.65.How many carbons are in the unknown molecule?

A)One carbon
B)Two carbons
C)Three carbons
D)Four carbons
E)Six carbons

Question 29

Which proton in the following molecule has the greatest chemical shift?

Question 30

Which compound would produce the ¹H NMR spectrum below?

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

Question 31

The mass spectrum for an unknown molecule has an M⁺ peak with a relative intensity of 100 and an M + 1 peak with a relative intensity of 9.905.How many carbons are in the unknown molecule?

A)1 carbon
B)5 carbons
C)9 carbons
D)10 carbons
E)100 carbons

Question 32

Which of the following is the base peak?

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

Question 33

Which compound would produce the given ¹H NMR spectrum below?

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

Question 34

Which compound would produce the ¹H NMR spectrum below?

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

Question 35

How many chemically distinct hydrogen atoms are in the following molecule?

Question 36

Which m/z value would indicate that nitrogen was present in a sample?

A)m / z =13
B)m / z =100
C)m / z = 104
D)m / z =150
E)m / z = 155

Question 37

Which hydrogen in the following molecule has the greatest integration value?

Question 38

Give the expected splitting patterns for H_A,H_B,H_C,and H_D.

Question 39

Give the expected splitting pattern for the indicated hydrogen.

Question 40

How many chemically distinct hydrogen atoms are in the following molecule?

Question 41

How many distinct ¹³C NMR signals are expected for the following compound?

Question 42

Explain how you can use a mass spectrum to determine if a single chlorine is present in a molecule.

Question 43

Explain how the two following isomers can be distinguished using ¹H NMR without using a standard for comparison.

Question 44

For the following molecule,give the splitting patterns for H_A,H_B,and H_C.

Question 45

The mass spectrum for an unknown molecule has an M⁺ peak with a relative intensity of 12.5 and an M + 1 peak with a relative intensity of 2.48.How many carbons are in the unknown molecule?

Question 46

Is a chlorine or a bromine present in the molecule responsible for the following mass spectrum? Explain how you know.

Question 47

For the following molecule,give the splitting patterns for H_A and H_B.

Question 48

Sketch a predicted ¹H NMR spectrum for the following molecule.

Question 49

Is a chlorine or a bromine present in the molecule responsible for the following mass spectrum? Explain how you know.

Question 50

The mass spectrum for an unknown molecule has an M⁺ peak with a relative intensity of 100 and an M + 1 peak with a relative intensity of 5.5.How many carbons are in the unknown molecule?

Question 51

Draw a splitting diagram for H_A and indicate the expected splitting pattern.

Question 52

Explain how coupling constants can be used to determine whether an NMR spectrum represents compound A or compound B.

Question 53

Explain how you can use a mass spectrum to determine if a single nitrogen is present in a molecule.

Question 54

For the following molecule,give the splitting patterns for H_A,H_B,and H_C.

Question 55

Draw a splitting diagram for H_A and indicate the expected splitting pattern.

Question 56

How many distinct ¹³C NMR signals are expected for the following compound?

Question 57

Sketch a predicted ¹H NMR spectrum for the following molecule.

Question 58

Label the base peak and the M⁺peak in the following mass spectrum.

Question 59

Sketch a predicted ¹H NMR spectrum for the following molecule.

Question 60

A molecule has the formula C₄H₉Cl,and its ¹H NMR spectrum has only one singlet at 1.49 ppm.Give the structure of this molecule.