Chapter 14, Problem 47P

1. (a) (a.1)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{1}}\text{H}\text{NMR}$ spectrum has to be determined.

Concept introduction:

The number of signals in ${}^{\text{1}}\text{H}\text{NMR}$ is equal to the number of chemically non-equivalent protons.  The protons in the different chemical environment are called chemically non-equilvalent protons and the protons in the same chemical environment are called chemically equivalent protons.

For each set of chemically equivalent protons, there will be one signal. For example, the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum of ethanol $\left(\text{C}\underset{\text{a}}{{\text{H}}_{\text{3}}}-\text{C}\underset{\text{b}}{{\text{H}}_{\text{2}}}-\text{O}\underset{\text{c}}{\text{H}}\right)$ will show 3 signals because there are 3 sets of chemically equivalent protons labelled as a, b and c.

Answer to Problem 47P

Compound (1) will show 5 signals in its ${}^{\text{1}}\text{H}\text{NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent protons in a compound produces a separate signal in ${}^1\text{H}\text{NMR}$.  There are 5 sets of chemically equivalent protons in this compound labelled as a, b, c, d and e.  Thus, the number of signals expected is 5.

(a.2)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{1}}\text{H}\text{NMR}$ spectrum has to be explained.

Concept introduction:

The number of signals in ${}^{\text{1}}\text{H}\text{NMR}$ is equal to the number of chemically non-equivalent protons. The protons in the different chemical environment are called chemically non-equilvalent protons and the protons in the same chemical environment are called chemically equivalent protons.

For each set of chemically equivalent protons, there will be one signal. For example, the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum of ethanol $\left(\text{C}\underset{\text{a}}{{\text{H}}_{\text{3}}}-\text{C}\underset{\text{b}}{{\text{H}}_{\text{2}}}-\text{O}\underset{\text{c}}{\text{H}}\right)$ will show 3 signals because there are 3 sets of chemically equivalent protons labelled as a, b and c.

Answer to Problem 47P

Compound (2) will show 5 signals in its ${}^{\text{1}}\text{H}\text{NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent protons in a compound produces a separate signal in ${}^1\text{H}\text{NMR}$. There are 5 sets of chemically equivalent protons in this compound labelled as a, b, c, d and e. Thus, the number of signals expected is 5.

(a.3)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{1}}\text{H}\text{NMR}$ spectrum has to be explained.

Concept introduction:

The number of signals in ${}^{\text{1}}\text{H}\text{NMR}$ is equal to the number of chemically non-equivalent protons. The protons in the different chemical environment are called chemically non-equilvalent protons and the protons in the same chemical environment are called chemically equivalent protons.

For each set of chemically equivalent protons, there will be one signal. For example, the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum of ethanol $\left(\text{C}\underset{\text{a}}{{\text{H}}_{\text{3}}}-\text{C}\underset{\text{b}}{{\text{H}}_{\text{2}}}-\text{O}\underset{\text{c}}{\text{H}}\right)$ will show 3 signals because there are 3 sets of chemically equivalent protons labelled as a, b and c.

Answer to Problem 47P

Compound (3) will show 4 signals in its ${}^{\text{1}}\text{H}\text{NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent protons in a compound produces a separate signal in ${}^1\text{H}\text{NMR}$.  There are 4 sets of chemically equivalent protons in this compound labelled as a, b, c and d.  Thus, the number of signals expected is 4.

(a.4)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{1}}\text{H}\text{NMR}$ spectrum has to be explained.

Concept introduction:

The number of signals in ${}^{\text{1}}\text{H}\text{NMR}$ is equal to the number of chemically non-equivalent protons. The protons in the different chemical environment are called chemically non-equilvalent protons and the protons in the same chemical environment are called chemically equivalent protons.

For each set of chemically equivalent protons, there will be one signal. For example, the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum of ethanol $\left(\text{C}\underset{\text{a}}{{\text{H}}_{\text{3}}}-\text{C}\underset{\text{b}}{{\text{H}}_{\text{2}}}-\text{O}\underset{\text{c}}{\text{H}}\right)$ will show 3 signals because there are 3 sets of chemically equivalent protons labelled as a, b and c.

Answer to Problem 47P

Compound (4) will show 2 signals in its ${}^{\text{1}}\text{H}\text{NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent protons in a compound produces a separate signal in ${}^1\text{H}\text{NMR}$.  There are 2 sets of chemically equivalent protons in this compound labelled as a and b.  Thus, the number of signals expected is 2.

(a.5)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{1}}\text{H}\text{NMR}$ spectrum has to be explained.

Concept introduction:

The number of signals in ${}^{\text{1}}\text{H}\text{NMR}$ is equal to the number of chemically non-equivalent protons.  The protons in the different chemical environment are called chemically non-equilvalent protons and the protons in the same chemical environment are called chemically equivalent protons.

For each set of chemically equivalent protons, there will be one signal. For example, the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum of ethanol $\left(\text{C}\underset{\text{a}}{{\text{H}}_{\text{3}}}-\text{C}\underset{\text{b}}{{\text{H}}_{\text{2}}}-\text{O}\underset{\text{c}}{\text{H}}\right)$ will show 3 signals because there are 3 sets of chemically equivalent protons labelled as a, b and c.

Answer to Problem 47P

Compound (5) will show 3 signals in its ${}^{\text{1}}\text{H}\text{NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent protons in a compound produces a separate signal in ${}^1\text{H}\text{NMR}$.  There are 3 sets of chemically equivalent protons in this compound labelled as a, b and c.  Thus, the number of signals expected is 3.

(a.6)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{1}}\text{H}\text{NMR}$ spectrum has to be explained.

Concept introduction:

The number of signals in ${}^{\text{1}}\text{H}\text{NMR}$ is equal to the number of chemically non-equivalent protons.  The protons in the different chemical environment are called chemically non-equilvalent protons and the protons in the same chemical environment are called chemically equivalent protons.

For each set of chemically equivalent protons, there will be one signal. For example, the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum of ethanol $\left(\text{C}\underset{\text{a}}{{\text{H}}_{\text{3}}}-\text{C}\underset{\text{b}}{{\text{H}}_{\text{2}}}-\text{O}\underset{\text{c}}{\text{H}}\right)$ will show 3 signals because there are 3 sets of chemically equivalent protons labelled as a, b and c.

Answer to Problem 47P

Compound (6) will show 3 signals in its ${}^{\text{1}}\text{H}\text{NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent protons in a compound produces a separate signal in ${}^1\text{H}\text{NMR}$.  There are 3 sets of chemically equivalent protons in this compound labelled as a, b and c.  Thus, the number of signals expected is 3.

1. (b) (b.1)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{13}}\text{C NMR}$ spectrum has to be determined.

Concept introduction:

The signals in the spectrum of a compound are proportional to the number of carbons that are present in the different environment within the molecule.  The carbon which is present in the electron-rich environment shows a signal at a lower frequency and vice-versa.  Therefore, the carbons that are present nearest to the electron-withdrawing groups produce a high-frequency signal.

Answer to Problem 47P

Compound (1) will show 7 signals in its ${}^{\text{13}}\text{C NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent carbon in a compound produces a separate signal in ${}^{\text{13}}\text{C NMR}$.  There are 7 sets of chemically equivalent carbons in this compound labelled as a, b, c, d, e, f and g. Thus, the number of signals expected is 7.

(b.2)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{13}}\text{C NMR}$ spectrum has to be determined.

Concept introduction:

The signals in the spectrum of a compound are proportional to the number of carbons that are present in the different environment within the molecule.  The carbon which is present in the electron-rich environment shows a signal at a lower frequency and vice-versa.  Therefore, the carbons that are present nearest to the electron-withdrawing groups produce a high-frequency signal.

Answer to Problem 47P

Compound (2) will show 7 signals in its ${}^{\text{13}}\text{C NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent carbon in a compound produces a separate signal in ${}^{\text{13}}\text{C NMR}$.  There are 7 sets of chemically equivalent carbons in this compound labelled as a, b, c, d, e, f and g. Thus, the number of signals expected is 7.

(b.3)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{13}}\text{C NMR}$ spectrum has to be determined.

Concept introduction:

The signals in the spectrum of a compound are proportional to the number of carbons that are present in the different environment within the molecule.  The carbon which is present in the electron-rich environment shows a signal at a lower frequency and vice-versa.  Therefore, the carbons that are present nearest to the electron-withdrawing groups produce a high-frequency signal.

Answer to Problem 47P

Compound (3) will show 5 signals in its ${}^{\text{13}}\text{C NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent carbon in a compound produces a separate signal in ${}^{\text{13}}\text{C NMR}$.  There are 5 sets of chemically equivalent carbons in this compound labelled as a, b, c, d and e.  Thus, the number of signals expected is 5.

(b.4)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{13}}\text{C NMR}$ spectrum has to be determined.

Concept introduction:

The signals in the spectrum of a compound are proportional to the number of carbons that are present in the different environment within the molecule.  The carbon which is present in the electron-rich environment shows a signal at a lower frequency and vice-versa.  Therefore, the carbons that are present nearest to the electron-withdrawing groups produce a high-frequency signal.

Answer to Problem 47P

Compound (4) will show 2 signals in its ${}^{\text{13}}\text{C NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent carbon in a compound produces a separate signal in ${}^{\text{13}}\text{C NMR}$.  There are 2 sets of chemically equivalent carbons in this compound labelled as a and b.  Thus, the number of signals expected is 2.

(b.5)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{13}}\text{C NMR}$ spectrum has to be determined.

Concept introduction:

The signals in the spectrum of a compound are proportional to the number of carbons that are present in the different environment within the molecule.  The carbon which is present in the electron-rich environment shows a signal at a lower frequency and vice-versa.  Therefore, the carbons that are present nearest to the electron-withdrawing groups produce a high-frequency signal.

Answer to Problem 47P

Compound (5) will show 2 signals in its ${}^{\text{13}}\text{C NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent carbon in a compound produces a separate signal in ${}^{\text{13}}\text{C NMR}$.  There are 2 sets of chemically equivalent carbons in this compound labelled as a and b.  Thus, the number of signals expected is 2.

(b.6)

Interpretation Introduction

Interpretation:

Number of signals expected in each of the following compounds in ${}^{\text{13}}\text{C NMR}$ spectrum has to be determined.

Concept introduction:

The signals in the spectrum of a compound are proportional to the number of carbons that are present in the different environment within the molecule.  The carbon which is present in the electron-rich environment shows a signal at a lower frequency and vice-versa.  Therefore, the carbons that are present nearest to the electron-withdrawing groups produce a high-frequency signal.

Answer to Problem 47P

Compound (6) will show 4 signals in its ${}^{\text{13}}\text{C NMR}$ spectrum.

Explanation of Solution

The set of chemically equivalent carbon in a compound produces a separate signal in ${}^{\text{13}}\text{C NMR}$.  There are 4 sets of chemically equivalent carbons in this compound labelled as a, b, c and d.  Thus, the number of signals expected is 4.