Question 1

In electron impact mass spectrometry (EIMS), what is being detected?

Accepted Answer

A) The molecular mass of the compound 
B) The molecular formula of the compound 
C) The mass to charge ratio of any ionic species 
D) The mass to charge ratio of any neutral species 
A) The molecular mass of the compound 
B) The molecular formula of the compound 
C) The mass to charge ratio of any ionic species 
D) The mass to charge ratio of any neutral species C

Question 2

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?

Accepted Answer

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

Question 3

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?

Accepted Answer

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

Question 4

You observe a compound that exhibits a mass spectrum with peak at 160 and a peak at 162, both of equal intensity.This compound contains:

Accepted Answer

A) Two chlorine atoms 
B) One iodine atom 
C) One bromine atom 
D) Two bromine atoms 
A) Two chlorine atoms 
B) One iodine atom 
C) One bromine atom 
D) Two bromine atoms

Question 5

What type of feature will be observed in the EI mass spectrum of chlorobenzene?

Accepted Answer

A) An absorption at 3100 cm-1 
B) A signal at 113. 
C) A signal at 112 and a signal at 114 in a ratio of 3:1 
D) A signal at 112 and a signal at 114 in a ratio of 1:1 
A) An absorption at 3100 cm-1 
B) A signal at 113. 
C) A signal at 112 and a signal at 114 in a ratio of 3:1 
D) A signal at 112 and a signal at 114 in a ratio of 1:1

Question 6

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

Question 7

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

Accepted Answer

A) A signal at 1600 cm-1 
B) A signal at 3300 cm-1 
C) A single mass peak at 92 amu 
D) Two mass peaks at 92 and 94 amu 
A) A signal at 1600 cm-1 
B) A signal at 3300 cm-1 
C) A single mass peak at 92 amu 
D) Two mass peaks at 92 and 94 amu

Question 8

Which of the following statement(s) is (are) true about a compound that has a molecular ion peak in its mass spectrum at mass 69 and shows a prominent peak in its IR spectrum at 2250 cm-1?

Accepted Answer

A) The compound has a molecular mass of 70. 
B) The compound contains a C=O group. 
C) The compound contains a cyano or alkyne group. 
D) Both (The compound has a molecular mass of 70) and (The compound contains a C=O group) are true statements. 
E) Both (The compound has a molecular mass of 70) and (The compound contains a cyano or alkyne group) are true statements. 
A) The compound has a molecular mass of 70. 
B) The compound contains a C=O group. 
C) The compound contains a cyano or alkyne group. 
D) Both (The compound has a molecular mass of 70) and (The compound contains a C=O group) are true statements. 
E) Both (The compound has a molecular mass of 70) and (The compound contains a cyano or alkyne group) are true statements.

Question 9

Examine the IR below and classify the compound.

Accepted Answer

A) Alcohol 
B) Arene 
C) Amine 
D) Ketone 
E) Carbocylic acid 
A) Alcohol 
B) Arene 
C) Amine 
D) Ketone 
E) Carbocylic acid

Question 10

Examine the IR below and classify the compound.

Accepted Answer

A) Alcohol 
B) Aldehyde 
C) Carboxylic acid 
D) Ketone 
A) Alcohol 
B) Aldehyde 
C) Carboxylic acid 
D) Ketone

Question 11

An IR spectrum has the following potentially important absorptions: 3091, 3067, 2963, 2921, 2252, 1603, 1499, 1455, 1416, 1078, 1031, 941, 735, and 696 cm-1.Indicate which structure corresponds to the IR data.

Accepted Answer

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

Question 12

Examine the IR below and classify the compound.

Accepted Answer

A) Alcohol 
B) Aldehyde 
C) Amine 
D) Ketone 
A) Alcohol 
B) Aldehyde 
C) Amine 
D) Ketone

Question 13

In a typical mass spectrum, a smaller signal is observed at a mass 1 amu higher than the molecular ion peak.Why?

Accepted Answer

A) Due to small impurities in the sample 
B) Machine error 
C) Because a small percentage of the compound will have a carbon that is the isotope 13C instead of 12C 
D) Because of fragmentation 
A) Due to small impurities in the sample 
B) Machine error 
C) Because a small percentage of the compound will have a carbon that is the isotope 13C instead of 12C 
D) Because of fragmentation

Question 14

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?

Accepted Answer

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

Question 15

The base peak in a mass spectrum corresponds to the most stable fragment.Propose a structure for a compound that is consistent with the following data.a) The molecular ion peak has m/z = 116.b) The base peak is at m/z = 59.c) The compound is composed of C, H and O atoms.d) The IR spectrum shows a strong absorbance at 3257 cm-1.

Accepted Answer

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

Question 16

Which of the following π bonds is IR inactive?

Accepted Answer

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

Question 17

What would be the molecular formula of rose oxide which contains C, H, and O and has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z =154?

Accepted Answer

A) C10H18O 
B) C9H14O2 
C) C10H2O2 
D) C8H10O3 
A) C10H18O 
B) C9H14O2 
C) C10H2O2 
D) C8H10O3

Question 18

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. 
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.

Question 19

When the phenol shown below is treated with KOH, it forms a product whose IR spectrum does not show an absorption in the 3200-3600 cm-1 region.Propose a structure for the product.

Accepted Answer

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

Question 20

Which of the following statements about the base peak of a mass spectrum is always true?

Accepted Answer

A) The base peak corresponds to the molecular ion. 
B) The base peak corresponds to the most abundant ion. 
C) The base peak corresponds to the lowest m/z. 
D) None of these. 
A) The base peak corresponds to the molecular ion. 
B) The base peak corresponds to the most abundant ion. 
C) The base peak corresponds to the lowest m/z. 
D) None of these.

Exam 13: Mass Spectrometry and Infrared Spectroscopy

In electron impact mass spectrometry (EIMS), what is being detected?

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?

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?

You observe a compound that exhibits a mass spectrum with peak at 160 and a peak at 162, both of equal intensity.This compound contains:

What type of feature will be observed in the EI mass spectrum of chlorobenzene?

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?

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

Which of the following statement(s) is (are) true about a compound that has a molecular ion peak in its mass spectrum at mass 69 and shows a prominent peak in its IR spectrum at 2250 cm-1?

Examine the IR below and classify the compound.

Examine the IR below and classify the compound.

An IR spectrum has the following potentially important absorptions: 3091, 3067, 2963, 2921, 2252, 1603, 1499, 1455, 1416, 1078, 1031, 941, 735, and 696 cm-1.Indicate which structure corresponds to the IR data.

Examine the IR below and classify the compound.

In a typical mass spectrum, a smaller signal is observed at a mass 1 amu higher than the molecular ion peak.Why?

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?

Which of the following π bonds is IR inactive?

What would be the molecular formula of rose oxide which contains C, H, and O and has two degrees of unsaturation and a molecular ion in its mass spectrum at m/z =154?

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

When the phenol shown below is treated with KOH, it forms a product whose IR spectrum does not show an absorption in the 3200-3600 cm-1 region.Propose a structure for the product.

Which of the following statements about the base peak of a mass spectrum is always true?

Structure and Bonding

Acids and Bases

Introduction to Organic Molecules and Functional Groups

Alkanes

Stereochemistry

Understanding Organic Reactions

Alkyl Halides and Nucleophilic Substitution

Alkyl Halides and Elimination Reactions

Alcohols, Ethers, and Related Compounds

Alkenes

Alkynes

Oxidation and Reduction

Nuclear Magnetic Resonance Spectroscopy

Radical Reactions

Conjugation, Resonance, and Dienes

Benzene and Aromatic Compounds

Reactions of Aromatic Compounds

Carboxylic Acids and the Acidity of the O-H Bond

Introduction to Carbonyl Chemistry;

Aldehydes and Ketones Nucleophilic Addition

Carboxylic Acids and Derivatives

Substitution Reactions of Carbonyl Compounds at the Alpha-Carbon

Carbonyl Condensation Reactions

Amines

Carbon-Carbon Bond Forming Reactions in Organic Synthesis

Pericyclic Reactions

Carbohydrates

Amino Acids and Proteins

Synthetic Polymers

Lipids

Filters

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?

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?

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?

Which of the following statement(s) is (are) true about a compound that has a molecular ion peak in its mass spectrum at mass 69 and shows a prominent peak in its IR spectrum at 2250 cm^-1?

An IR spectrum has the following potentially important absorptions: 3091, 3067, 2963, 2921, 2252, 1603, 1499, 1455, 1416, 1078, 1031, 941, 735, and 696 cm^-1.Indicate which structure corresponds to the IR data.

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?

When the phenol shown below is treated with KOH, it forms a product whose IR spectrum does not show an absorption in the 3200-3600 cm^-1 region.Propose a structure for the product.