Question 1

What type of signal(s) would you observe in the mass and/or infrared spectrum of the following compound? -1 D) A signal at 1720 cm-1" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  A signal at 96 amu
B)  Two signals at 112 and 114 amu
C)  A signal at 1600 cm-1
D)  A signal at 1720 cm-1E) A) and D)
F) A) and C)

Question 2

Which of the following π bonds is IR inactive?

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) All of the above
F) C) and D)

Question 3

Which of the following structures is consistent with a compound that displays a molecular ion peak at 56 and infrared signals at 2250 and 3600-3200 cm-1? -1?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) C) and D)
F) B) and C) B

Question 4

Which of the following statements is (are) true about a compound that has molecular ion peaks in its mass spectrum at mass 170 and 172 and shows prominent peaks in its IR spectrum at 3150-3000 and 1600 cm-1?

Accepted Answer

A)  The compound is not pure.
B)  The compound contains a halogen.
C)  The compound contains an OH group and Csp3-H hybridized bonds.
D)  Both (The compound is not pure) and (The compound contains a halogen) are true statements.
E)  Both (The compound is not pure) and (The compound contains an OH group and Csp3-H hybridized bonds) are true statements.F) A) and C)
G) A) and B)

Question 5

Examine the IR below and classify the compound.

Accepted Answer

A)  Alcohol
B)  Aldehyde
C)  Amine
D)  Ketone
E)  Carboxylic acidF) A) and B)
G) All of the above

Question 6

Examine the IR below and classify the compound.

Accepted Answer

A)  Alcohol
B)  Arene
C)  Amine
D)  Ketone
E)  Carbocylic acidF) B) and C)
G) C) and D)

Question 7

A compound X shows a molecular ion peak at m/z 72 in its mass spectrum,and a strong peak at ~1715 cm-1 in its IR spectrum.Which structures are possible for compound X? -1 in its IR spectrum.Which structures are possible for compound X?   A) I B) II C) III D) I and II" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  I and IIE) A) and C)
F) All of the above

Question 8

Examine the IR below and classify the compound.

Accepted Answer

A)  Alcohol
B)  Aldehyde
C)  Carboxylic acid
D)  KetoneE) A) and B)
F) A) and C)

Question 9

Which of the following statements is (are) true about a compound that has a molecular ion peak in its mass spectrum at mass 94 and shows prominent peaks in its IR spectrum at 3600-3200 and 1600 cm-1?

Accepted Answer

A)  The compound has a molecular mass of 94.
B)  The compound contains a C=O group and Csp3-H hybridized bonds.
C)  The compound contains an OH group and a benzene ring.
D)  Both (The compound has a molecular mass of 94) and (The compound contains a C=O group and Csp3-H hybridized bonds) are true statements.
E)  Both (The compound has a molecular mass of 94) and (The compound contains an OH group and a benzene ring) are true statements.F) C) and D)
G) A) and C)

Question 10

Examine the IR below and classify the compound.

Accepted Answer

A)  Alkane
B)  Carboxylic acid
C)  Alcohol
D)  AlkeneE) A) and C)
F) None of the above

Question 11

Compared to a C-H bond,a C-D bond will vibrate where in the infrared spectrum?

Accepted Answer

A)  Higher molecular weight
B)  Lower molecular weight
C)  Lower wavenumbers
D)  Higher wavenumbersE) All of the above
F) None of the above C

Question 12

Which of the following structures is consistent with a compound that displays a molecular ion peak at 103 and infrared signals at 2250 and 1600 cm-1? -1?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) None of the above
F) B) and C)

Question 13

Which of the following structures is consistent with a compound that displays a molecular ion peak at 84 and infrared signals at 3000-2850 cm-1 and no signals between 3000-3300 cm-1? -1 and no signals between 3000-3300 cm-1?   A) I B) II C) III D) IV" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I
B)  II
C)  III
D)  IVE) B) and D)
F) A) and C)

Question 14

You are given a bottle of an organic liquid and told it must be either cyclohexane or 1-hexene.Which of the following statements is (are) true about these two compounds? -1 but cyclohexane will not. C) Both cyclohexane and 1-hexene will show C-H absorptions at about 2950 cm-1. D) Statements (1-Hexene will show an absorption at 1650 cm-1 but cyclohexane will not) and (Both cyclohexane and 1-hexene will show C-H absorptions at about 2950 cm-1) are both true. E) Statements (The two compounds can be differentiated by their mass spectra because they will have molecular ions at different masses) ,(1-Hexene will show an absorption at 1650 cm-1 but cyclohexane will not) ,and (Both cyclohexane and 1- hexene will show C-H absorptions at about 2950 cm-1) are all true." class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  The two compounds can be differentiated by their mass spectra because they will have molecular ion peaks at different m/z.
B)  1-Hexene will show an absorption at 1650 cm-1 but cyclohexane will not.
C)  Both cyclohexane and 1-hexene will show C-H absorptions at about 2950 cm-1.
D)  Statements (1-Hexene will show an absorption at 1650 cm-1 but cyclohexane will not) and (Both cyclohexane and 1-hexene will show C-H absorptions at about 2950 cm-1) are both true.
E)  Statements (The two compounds can be differentiated by their mass spectra because they will have molecular ions at different masses) ,(1-Hexene will show an absorption at 1650 cm-1 but cyclohexane will not) ,and (Both cyclohexane and 1- hexene will show C-H absorptions at about 2950 cm-1) are all true.F) All of the above
G) A) and D)

Question 15

Which of the following statements is (are) accurate about the IR spectrum of compounds I,II,and III below? -1. B) Compound II shows absorptions at 3200-3600 and 1650 cm-1. C) Compound III shows absorptions at 3200-3600 and 2950 cm-1. D) Both (Compound I shows absorptions at 2950 and 1700 cm-1) and (Compound II shows absorptions at 3200-3600 and 1650 cm-1) are true." class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  Compound I shows absorptions at 2950 and 1700 cm-1.
B)  Compound II shows absorptions at 3200-3600 and 1650 cm-1.
C)  Compound III shows absorptions at 3200-3600 and 2950 cm-1.
D)  Both (Compound I shows absorptions at 2950 and 1700 cm-1) and (Compound II shows absorptions at 3200-3600 and 1650 cm-1) are true.E) A) and B)
F) A) and C)

Question 16

Examine the IR below and classify the compound.

Accepted Answer

A)  Alcohol
B)  Aldehyde
C)  Amine
D)  KetoneE) B) and C)
F) A) and D)

Question 17

The functional group region of an infrared spectrum is

Accepted Answer

A)  where the cations appear.
B)  greater than or equal to 1500 cm-1.
C)  less than 1500 cm-1.
D)  greater than or equal to 2500 cm-1.E) None of the above
F) A) and C)

Question 18

Consider the three organic compounds drawn below.Which of the following statements is (are) true about the IR spectra of I,II,and III? -1 and 1700 cm-1. B) II shows strong absorptions at 2950 cm-1 and 2250 cm-1. C) III shows strong absorptions at 2950 cm-1 and 3200-3600 cm-1. D) Statements (I shows strong absorptions at 2950 cm-1 and 1700 cm-1) and (III shows strong absorptions at 2950 cm-1 and 3200-3600 cm-1) are true." class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  I shows strong absorptions at 2950 cm-1 and 1700 cm-1.
B)  II shows strong absorptions at 2950 cm-1 and 2250 cm-1.
C)  III shows strong absorptions at 2950 cm-1 and 3200-3600 cm-1.
D)  Statements (I shows strong absorptions at 2950 cm-1 and 1700 cm-1) and (III shows strong absorptions at 2950 cm-1 and 3200-3600 cm-1) are true.E) All of the above
F) B) and D) D

Question 19

Why is the infrared absorption for the stretching motion of internal alkynes rarely observed?

Accepted Answer

A)  They do not form cations.
B)  They are too strong.
C)  Stretching in internal alkynes does not involve a change in dipole moment.
D)  They do not have hydrogens.E) B) and C)
F) A) and C)

Question 20

Which of the following statements is (are) true about the IR spectrum of the compound drawn below? -1 and 1720 cm-1. B) It shows absorptions at 3000-2850 cm-1 and 2150 cm-1. C) It shows absorptions at 2250 cm-1 and 1650 cm-1. D) It shows absorptions at 2250 cm-1 and 1720 cm-1. E) Both statements (It shows absorptions at 3000-2850 cm-1 and 2250 cm-1) and (It shows absorptions at 2250 cm-1 and 1720 cm-1) are true." class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  It shows absorptions at 3000-3150 cm-1 and 1720 cm-1.
B)  It shows absorptions at 3000-2850 cm-1 and 2150 cm-1.
C)  It shows absorptions at 2250 cm-1 and 1650 cm-1.
D)  It shows absorptions at 2250 cm-1 and 1720 cm-1.
E)  Both statements (It shows absorptions at 3000-2850 cm-1 and 2250 cm-1) and (It shows absorptions at 2250 cm-1 and 1720 cm-1) are true.F) B) and E)
G) A) and C)

Exam 31: Analyzing Molecular Motion and Infrared Spectroscopy

What type of signal(s) would you observe in the mass and/or infrared spectrum of the following compound?

Correct AnswerverifiedShow Answer

Which of the following π bonds is IR inactive?

Correct AnswerverifiedShow Answer

Which of the following structures is consistent with a compound that displays a molecular ion peak at 56 and infrared signals at 2250 and 3600-3200 cm-1?

Correct AnswerverifiedB

Which of the following statements is (are) true about a compound that has molecular ion peaks in its mass spectrum at mass 170 and 172 and shows prominent peaks in its IR spectrum at 3150-3000 and 1600 cm-1?

Correct AnswerverifiedShow Answer

Examine the IR below and classify the compound.

Correct AnswerverifiedShow Answer

Examine the IR below and classify the compound.

Correct AnswerverifiedShow Answer

A compound X shows a molecular ion peak at m/z 72 in its mass spectrum,and a strong peak at ~1715 cm-1 in its IR spectrum.Which structures are possible for compound X?

Correct AnswerverifiedShow Answer

Examine the IR below and classify the compound.

Correct AnswerverifiedShow Answer

Which of the following statements is (are) true about a compound that has a molecular ion peak in its mass spectrum at mass 94 and shows prominent peaks in its IR spectrum at 3600-3200 and 1600 cm-1?

Correct AnswerverifiedShow Answer

Examine the IR below and classify the compound.

Correct AnswerverifiedShow Answer

Compared to a C-H bond,a C-D bond will vibrate where in the infrared spectrum?

Correct AnswerverifiedC

Which of the following structures is consistent with a compound that displays a molecular ion peak at 103 and infrared signals at 2250 and 1600 cm-1?

Correct AnswerverifiedShow Answer

Which of the following structures is consistent with a compound that displays a molecular ion peak at 84 and infrared signals at 3000-2850 cm-1 and no signals between 3000-3300 cm-1?

Correct AnswerverifiedShow Answer

You are given a bottle of an organic liquid and told it must be either cyclohexane or 1-hexene.Which of the following statements is (are) true about these two compounds?

Correct AnswerverifiedShow Answer

Which of the following statements is (are) accurate about the IR spectrum of compounds I,II,and III below?

Correct AnswerverifiedShow Answer

Examine the IR below and classify the compound.

Correct AnswerverifiedShow Answer

The functional group region of an infrared spectrum is

Correct AnswerverifiedShow Answer

Consider the three organic compounds drawn below.Which of the following statements is (are) true about the IR spectra of I,II,and III?

Correct AnswerverifiedD

Why is the infrared absorption for the stretching motion of internal alkynes rarely observed?

Correct AnswerverifiedShow Answer

Which of the following statements is (are) true about the IR spectrum of the compound drawn below?

Correct AnswerverifiedShow Answer

Correct Answer
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Which of the following structures is consistent with a compound that displays a molecular ion peak at 56 and infrared signals at 2250 and 3600-3200 cm^-1?

Correct Answer
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B

Which of the following statements is (are) true about a compound that has molecular ion peaks in its mass spectrum at mass 170 and 172 and shows prominent peaks in its IR spectrum at 3150-3000 and 1600 cm^-1?

Correct Answer
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A compound X shows a molecular ion peak at m/z 72 in its mass spectrum,and a strong peak at ~1715 cm^-1 in its IR spectrum.Which structures are possible for compound X?

Correct Answer
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Which of the following statements is (are) true about a compound that has a molecular ion peak in its mass spectrum at mass 94 and shows prominent peaks in its IR spectrum at 3600-3200 and 1600 cm^-1?

Correct Answer
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C

Which of the following structures is consistent with a compound that displays a molecular ion peak at 103 and infrared signals at 2250 and 1600 cm^-1?

Correct Answer
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Which of the following structures is consistent with a compound that displays a molecular ion peak at 84 and infrared signals at 3000-2850 cm^-1 and no signals between 3000-3300 cm^-1?

Correct Answer
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Correct Answer
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D

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