Question 1

Which of the following molecules has the most acidic hydrogen atoms?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

Accepted Answer

The presence of electronegative atoms (in this case, oxygen) near a hydrogen atom makes it more acidic. In molecule III, the oxygen atom is directly attached to the hydrogen atom, making it the most acidic. Molecules I, II, and IV all have carbons attached to their most acidic hydrogen, which decreases the acidity compared to molecule III.

Question 2

Which of the following ions is aromatic?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

Accepted Answer

I

Question 3

How many ¹³CNMR signals does the following compound exhibit? A) 4 B) 5 C) 6 D) 8

Accepted Answer

The compound has 6 unique groups of protons that are chemically non-equivalent and will give rise to separate ¹³CNMR signals.

Question 4

Which of the following statements about benzene is true?&#10;A) Benzene is a saturated hydrocarbon.&#10;B) Benzene undergoes addition reactions.&#10;C) Benzene has five degrees of unsaturation.&#10;D) Benzene undergoes substitution reactions.

Accepted Answer

Benzene undergoes substitution reactions, not addition reactions. It is also an unsaturated hydrocarbon with six degrees of unsaturation, not five.

Question 5

What is the correct assignment of the number of signals in the ¹³C NMR spectra of the following disubstituted benzene derivatives? A) I = 3 signals; II = 3 signals; III = 2 signals. B) I = 3 signals; II = 4 signals; III = 2 signals. C) I = 6 signals; II = 6 signals; III = 6 signals. D) I = 3 signals; II = 4 signals; III = 3 signals.

Accepted Answer

The number of signals in the NMR spectra of disubstituted benzene derivatives can be determined by considering the number of unique proton environments. 
I. has three unique proton environments, one for the two protons adjacent to the substituent (-CH2-) and two for the aromatic protons. Therefore, it should give three signals in the NMR spectrum.
II. has four unique proton environments, one for the two protons adjacent to the substituent (-CH2-), one for the methyl group (-CH3), and two for the aromatic protons. Therefore, it should give four signals in the NMR spectrum.
III. has two unique proton environments, one for each of the two substituents (-NO2 and -Cl). Each substituent will cause a shift in the position of the aromatic protons, leading to two distinct signals in the NMR spectrum.
Therefore, the correct assignment of signals is I = 3 signals, II = 4 signals, III = 2 signals, making option B the best choice.

Question 6

Rank the following compounds in order of decreasing acidity, starting with the most acidic.  &#10;A) I > II > III&#10;B) III > II > I&#10;C) III > I > II&#10;D) I > III > II

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Question 7

What is the structure of a compound of molecular formula C₁₀H₁₄O₂ that shows a strong IR absorption at 3150 - 2850 cm^-1 and gives the following ¹H NMR absorptions: 1.4 (triplet, 6H); 4.0 (quartet, 4H); and 6.8 (singlet, 4H) ppm.

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

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Question 8

Which of the following is not one of the H&#252;ckel's criteria for aromaticity?&#10;A) The molecule must be cyclic.&#10;B) The molecule must be planar.&#10;C) The molecule must be completely conjugated.&#10;D) The molecule must have 4n pi electrons.

Accepted Answer

Hückel's criteria for aromaticity states that a molecule must be cyclic, planar, and completely conjugated. The correct number of pi electrons for aromaticity is 4n+2, not 4n. Therefore, choice D is not one of Hückel's criteria for aromaticity.

Question 9

What is the IUPAC name of the following compound?  &#10;A) 3,6-Dichloroaniline&#10;B) 2,5-Dichloroaniline&#10;C) 2,5-Dichloroaminobenzene&#10;D) 2,5-Dichloroanisole

Accepted Answer

The compound has two chlorine atoms and an amino group attached to a benzene ring. The amino group is on the 2nd carbon and the two chlorine atoms are on the 5th and 6th carbons. Therefore, the correct IUPAC name is 2,5-Dichloroaniline.

Question 10

What orbitals are used to form the bond indicated in the following molecule? A) Csp² - Csp² B) Csp² - C2p C) C2p - C2p D) Csp³ - Csp³

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Question 11

What is the correct assignment of the names of the following fused aromatic compounds?  &#10;A) I = naphthalene; II = anthracene; III = phenanthrene.&#10;B) I = naphthalene; II = phenanthrene; III = anthracene.&#10;C) I = naphthalene; II = phenanthrene; III = benzo[a]pyrene.&#10;D) I = anthracene; II = naphthalene; III = phenanthrene.

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Question 12

What is the correct assignment of the names of the following substituted benzenes?  &#10;A) I = Styrene; II = aniline; III = anisole.&#10;B) I = Toluene; II = anisole; III = styrene.&#10;C) I = Styrene; II = anisole; III = phenol.&#10;D) I = Toluene; II = aniline; III = anisole.

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Question 13

What is the IUPAC name of the following compound?  &#10;A) 2-Nitro-5-carboxychlorobenzene&#10;B) 2-Chloro-4-carboxynitrobenzene&#10;C) 2-Chloro-1-nitro-4-benzoic acid&#10;D) 3-Chloro-4-nitrobenzoic acid

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Question 14

What is the correct assignment of the names of the following aromatic heterocycles?  &#10;A) I = pyridine; II = pyrimidine; III = furan.&#10;B) I = pyrimidine; II =pyrrole; III = furan.&#10;C) I = pyridine; II = pyrrole; III = furan.&#10;D) I = pyrimidine; II = pyrrole; III = tetrahydrofuran.

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Question 15

Which of the following statements about the structure of benzene is not true?&#10;A) Benzene is planar.&#10;B) Benzene has three short double bonds alternating with three longer single bonds.&#10;C) The electrons in the pi bonds are delocalized around the ring.&#10;D) Benzene has six pi electrons.

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Question 16

What is the correct assignment of the names of the following substituted benzenes?  &#10;A) I = Phenol; II = anisole; III = toluene.&#10;B) I = Benzaldehyde; II = phenol; III = anisole.&#10;C) I = Benzaldehyde; II = phenol; III = toluene.&#10;D) I = Phenol; II = anisole; III = styrene.

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Question 17

Which of the following heterocycles is not aromatic?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 18

What is the IUPAC name of the following compound?  &#10;A) 3-Bromo-1-chloro-4-toluene&#10;B) 2-Bromo-4-chlorotoluene&#10;C) 4-Chloro-2-bromo-1-toluene&#10;D) 2-Bromo-4-chloroanisole

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Question 19

Which of the following is not a criterion for antiaromaticity?&#10;A) The molecule must be cyclic.&#10;B) The molecule must have (4n + 2) pi electrons.&#10;C) The molecule must be planar.&#10;D) The molecule must be completely conjugated.

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Question 20

What is the IUPAC name of the following compound?  &#10;A) 1-Chloro-4-ethyl-3-propylbenzene&#10;B) 1-Chloro-4-ethyl-5-propylbenzene&#10;C) 4-Chloro-1-ethyl-2-propylbenzene&#10;D) 4-Chloro-2-propyltoluene

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Question 21

Which of the following compounds is aromatic?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 22

Why is the following compound not aromatic?  &#10;A) It has 4n pi electrons.&#10;B) It is not cyclic.&#10;C) It has 4n+2 pi electrons.&#10;D) The $\pi$ electron system is not continuous.

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Question 23

What orbitals are used to form the indicated bond? A) sp³ B) sp² C) p D) sp³ and sp²

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Question 24

Where do the protons in benzene appear in the ¹H NMR spectrum? A) Around 1600 cm^-1 B) Around 120 ppm C) Around 0 ppm D) Around 7 ppm

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Question 25

Which of the following compounds is not aromatic?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 26

How many different proton signals would the following compound show in its ¹H NMR spectrum? A) 1 B) 3 C) 5 D) 6

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Question 27

What is the correct structure for 1-bromo-2,4-dimethoxybenzene?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 28

Which of the following ions is aromatic?  &#10;A) Only I and II&#10;B) Only II and III&#10;C) Only III and IV&#10;D) Only II and IV

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Question 29

What compound is consistent with the following ¹H NMR spectrum? A) phenol B) anisole C) 4-bromoanisole D) 4-bromotoluene

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Question 30

Which of the following compounds is not aromatic?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 31

What is the name of the following compound?  &#10;A) 2,6-dimethylbenzene&#10;B) 5-methyltoluene&#10;C) anisole&#10;D) 1,3-dimethylbenzene

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Question 32

What is the correct structure for toluene?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 33

What is the name of the following compound?  &#10;A) meta-bromophenol&#10;B) para-hydroxybenzene&#10;C) 3-bromoanisole&#10;D) 6-methoxy-2-bromobenzene

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Question 34

What is the correct structure for anisole?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 35

Why is the following compound not aromatic?  &#10;A) It has 4n electrons.&#10;B) It is not cyclic.&#10;C) It has 4n+2 electrons.&#10;D) The $\pi$ electron system is not continuous.

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Question 36

Which of the following compounds is aromatic?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 37

What is the correct structure for aniline?  &#10;A) I&#10;B) II&#10;C) III&#10;D) IV

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Question 38

Which of the following statements about the molecular orbital (MO) theory is true?&#10;A) When two p orbitals of similar phase overlap side-by-side, a $\pi$* antibonding molecular orbital is formed.&#10;B) When two p orbitals of opposite phase overlap side-by-side, a $\pi$ bonding molecular orbital is formed.&#10;C) A $\pi$ bonding molecular orbital is higher in energy than the two atomic p orbitals from which it is formed.&#10;D) A $\pi$* antibonding molecular orbital is higher in energy than the two atomic p orbitals from which it is formed.