Question 1

How many sets of equivalent protons are there in hexane?

Accepted Answer

B

Question 2

Which of the following is not true regarding ¹H NMR spectroscopy?

Accepted Answer

The chemical shift (δ) for a particular proton is independent of the magnetic field strength of the instrument used; it is a relative measure and remains constant across different instruments.

Question 3

Which C₄H₉Br compound gives a triplet at approximately 3.5 ppm in the ¹H NMR spectrum?

Accepted Answer

A

Question 4

What is the appearance of the signal corresponding to the CH₂ protons in the ¹H NMR spectrum of ethyl methyl ether, CH₃CH₂OCH₃?

Accepted Answer

The signal for the CH3CH2O- protons in ethyl methyl ether will appear as a quartet due to the splitting caused by the three protons on the adjacent CH2 group.

Question 5

How many sets of equivalent protons are there in 3-methylhexane?

Accepted Answer

The answer of How many sets of equivalent protons are...

Question 6

Which feature in the ¹H NMR spectrum provides information about the number of neighboring protons of each proton in the compound?

Accepted Answer

Multiplicity in the NMR spectrum provides information about the number of neighboring protons of each proton in the compound. The number of signals indicates the number of non-equivalent proton environments, integral gives the relative number of protons in each environment, and chemical shift provides information about the electronic environment of the proton.

Question 7

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of ethane?

Accepted Answer

The splitting of the signal for the methyl protons of ethane would result in a singlet in the NMR spectrum because there are no neighboring protons to cause splitting through coupling.

Question 8

Which feature in the ¹H NMR spectrum provides information about the relative number of each type of proton in a compound?

Accepted Answer

The integral in the NMR spectrum provides information about the relative number of each type of proton in a compound. The integral represents the area under the peak corresponding to each type of proton, which is proportional to the number of those protons in the molecule. The number of signals corresponds to the number of chemically distinct types of protons in the molecule, the splitting provides information about the neighboring protons in the same chemical environment, and the chemical shift indicates the electronic environment around each type of proton.

Question 9

How many sets of equivalent protons are there in 2-methylhexane?

Accepted Answer

2-methylhexane has 6 sets of equivalent protons: three sets in the methyl groups (one in the 2-methyl group and two terminal methyl groups in the hexane chain), two sets in the methylene groups (the ones adjacent to the terminal methyl groups), and one set in the methine group (the one adjacent to the 2-methyl group).

Question 10

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 2-methylpropane?

Accepted Answer

The answer of Which of the following combinations of peaks...

Question 11

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 1,4-dimethyoxyethane, CH₃OCH₂CH₂CH₂CH₂OCH₃?

Accepted Answer

The answer of Which of the following combinations of peaks...

Question 12

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 1,2-dimethyoxyethane, CH₃OCH₂CH₂OCH₃?

Accepted Answer

1,2-Dimethoxyethane, CH3OCH2CH2OCH3, has two types of protons in a symmetrical environment, leading to two distinct singlets in its NMR spectrum.

Question 13

Which feature in the ¹H NMR spectrum provides information about the number of types of different protons in a compound?

Accepted Answer

The number of signals in an NMR spectrum corresponds to the number of unique types of protons in a compound. Each type of proton will give rise to a separate signal in the spectrum, and the number of signals therefore indicates the number of distinct sets of protons in the molecule.

Question 14

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of 1-bomo-2-methylpropane?

Accepted Answer

The methyl protons in 1-bromo-2-methylpropane will split into a doublet due to the two adjacent protons on the neighboring carbon atom. The splitting pattern is given by the n+1 rule, where n is the number of neighboring protons. In this case, n=2 (two protons on the neighboring carbon), so the splitting pattern will be a doublet (2+1=3).

Question 15

Which of the following is not true regarding ¹H NMR spectroscopy?

Accepted Answer

In NMR spectroscopy, a "downfield" peak appears at a higher value of δ, not a lower value.

Question 16

Which of the following combinations of peaks appears in the ¹H NMR spectrum of butane?

Accepted Answer

The ¹H NMR spectrum of butane shows two sets of equivalent protons: the two methyl protons (CH3) and the two methylene protons (CH2). The CH3 group is a triplet, since it is split by the adjacent methylene protons into three peaks with a ratio of 1:2:1. The CH2 group is a quartet, since it is split by the two adjacent methyl protons into four peaks with a ratio of 1:3:3:1. Therefore, the spectrum shows a combination of a triplet and a quartet.

Question 17

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 2,3-dimethylbutane?

Accepted Answer

The answer of Which of the following combinations of peaks...

Question 18

Which of the following combinations of peaks appears in the ¹H NMR spectrum of diethyl ether, CH₃CH₂OCH₂CH₃?

Accepted Answer

Diethyl ether (CH3CH2OCH2CH3) has two types of protons: those in the methylene groups (-CH2-) adjacent to the oxygen, and those in the methyl groups (-CH3) at the ends. The methylene protons are split into a quartet by the three equivalent protons on the adjacent methyl group, and the methyl protons are split into a triplet by the two equivalent protons on the adjacent methylene group.

Question 19

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of propane?

Accepted Answer

The methyl protons of propane are equivalent and are surrounded by two neighboring protons on adjacent carbon atoms. This results in a triplet splitting pattern in the NMR spectrum.

Question 20

Which feature in the ¹H NMR spectrum provides information about the electronic environment of the protons in a compound?

Accepted Answer

Chemical shift is the feature in the NMR spectrum that provides information about the electronic environment of the protons in a compound. The chemical shift is affected by the electron density around the proton and can be used to determine the functional groups present in a molecule. The number of signals, integral, and splitting provide information about the number of different types of protons present, the relative number of protons in each type, and the neighboring protons, respectively.

Quiz 13: Nuclear Magnetic Resonance Spectroscopy

How many sets of equivalent protons are there in hexane?

Which of the following is not true regarding 1H NMR spectroscopy?

Which C4H9Br compound gives a triplet at approximately 3.5 ppm in the 1H NMR spectrum?

What is the appearance of the signal corresponding to the CH2 protons in the 1H NMR spectrum of ethyl methyl ether, CH3CH2OCH3?

How many sets of equivalent protons are there in 3-methylhexane?

Which feature in the 1H NMR spectrum provides information about the number of neighboring protons of each proton in the compound?

What is the splitting of the signal in the 1H NMR spectrum for the methyl protons of ethane?

Which feature in the 1H NMR spectrum provides information about the relative number of each type of proton in a compound?

How many sets of equivalent protons are there in 2-methylhexane?

Which of the following combinations of peaks appears in the 1H NMR spectrum of 2-methylpropane?

Which of the following combinations of peaks appears in the 1H NMR spectrum of 1,4-dimethyoxyethane, CH3OCH2CH2CH2CH2OCH3?

Which of the following combinations of peaks appears in the 1H NMR spectrum of 1,2-dimethyoxyethane, CH3OCH2CH2OCH3?

Which feature in the 1H NMR spectrum provides information about the number of types of different protons in a compound?

What is the splitting of the signal in the 1H NMR spectrum for the methyl protons of 1-bomo-2-methylpropane?

Which of the following is not true regarding 1H NMR spectroscopy?

Which of the following combinations of peaks appears in the 1H NMR spectrum of butane?

Which of the following combinations of peaks appears in the 1H NMR spectrum of 2,3-dimethylbutane?

Which of the following combinations of peaks appears in the 1H NMR spectrum of diethyl ether, CH3CH2OCH2CH3?

What is the splitting of the signal in the 1H NMR spectrum for the methyl protons of propane?

Which feature in the 1H NMR spectrum provides information about the electronic environment of the protons in a compound?

Which of the following is not true regarding ¹H NMR spectroscopy?

Which C₄H₉Br compound gives a triplet at approximately 3.5 ppm in the ¹H NMR spectrum?

What is the appearance of the signal corresponding to the CH₂ protons in the ¹H NMR spectrum of ethyl methyl ether, CH₃CH₂OCH₃?

Which feature in the ¹H NMR spectrum provides information about the number of neighboring protons of each proton in the compound?

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of ethane?

Which feature in the ¹H NMR spectrum provides information about the relative number of each type of proton in a compound?

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 2-methylpropane?

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 1,4-dimethyoxyethane, CH₃OCH₂CH₂CH₂CH₂OCH₃?

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 1,2-dimethyoxyethane, CH₃OCH₂CH₂OCH₃?

Which feature in the ¹H NMR spectrum provides information about the number of types of different protons in a compound?

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of 1-bomo-2-methylpropane?

Which of the following is not true regarding ¹H NMR spectroscopy?

Which of the following combinations of peaks appears in the ¹H NMR spectrum of butane?

Which of the following combinations of peaks appears in the ¹H NMR spectrum of 2,3-dimethylbutane?

Which of the following combinations of peaks appears in the ¹H NMR spectrum of diethyl ether, CH₃CH₂OCH₂CH₃?

What is the splitting of the signal in the ¹H NMR spectrum for the methyl protons of propane?

Which feature in the ¹H NMR spectrum provides information about the electronic environment of the protons in a compound?