Chapter 12, Problem 12.12SP

(a)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$ and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 1

Explanation of Solution

The structure of the given molecule is,

Figure 2

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 1

So, the stretching frequencies of $\text{C=C}$ is $1660{\text{cm}}^{-1}$, $\text{C-C}$ is $1200{\text{cm}}^{-1}$ and $\text{C-H}$ is $3000{\text{cm}}^{-1}$.

(b)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$ and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 3

Explanation of Solution

The structure of the given molecule is,

Figure 4

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 3

So, the stretching frequencies of $\text{C-O}$ is $1050{\text{cm}}^{-1}$, $\text{C-C}$ is $1200{\text{cm}}^{-1}$, $\text{C-H}$ is $3000{\text{cm}}^{-1}$ and $\text{O-H}$ is $3300{\text{cm}}^{-1}$

(c)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$ and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 5

Explanation of Solution

The structure of the given molecule is,

Figure 6

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 5

So, the stretching frequencies of $\text{C-C}$ is $1200{\text{cm}}^{-1}$, $\text{C-H}$ is $3000{\text{cm}}^{-1}$ and $\text{C=O}$ is $1710{\text{cm}}^{-1}$.

(d)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$ and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 7

Explanation of Solution

The structure of the given molecule is,

Figure 8

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 7

So, the stretching frequencies of $\text{C-C}$ is $1200{\text{cm}}^{-1}$, $\text{C-H}$ is $3000{\text{cm}}^{-1}$ and $\text{C}\equiv \text{C}$ is $2200{\text{cm}}^{-1}$.

(e)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$  and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 9

Explanation of Solution

The structure of the given molecule is,

Figure 10

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 9

So, the stretching frequencies of $\text{C-N}$ is $1200{\text{cm}}^{-1}$ and $\text{N-H}$ is $3300{\text{cm}}^{-1}$.

(f)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule is to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$  and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 11

Explanation of Solution

The structure of the given molecule is,

Figure 12

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 11

So, the stretching frequencies of $\text{C-C}$ is $1200{\text{cm}}^{-1}$, $\text{C-H}$ is $3000{\text{cm}}^{-1}$, $\text{C=O}$ is $1710{\text{cm}}^{-1}$, $\text{C-O}$ is $1050{\text{cm}}^{-1}$ and $\text{O-H}$ is $3300{\text{cm}}^{-1}$.

(g)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$  and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 13

Explanation of Solution

The structure of the given molecule is,

Figure 14

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 13

So, the stretching frequencies of $\text{C-C}$ is $1200{\text{cm}}^{-1}$, $\text{C-H}$ is $3000{\text{cm}}^{-1}$ and $\text{C}\equiv \text{N}$ is $2200{\text{cm}}^{-1}$.

(h)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$ and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 15

Explanation of Solution

The structure of the given molecule is,

Figure 16

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 15

So, the stretching frequencies of $\text{C-O}$ is $1050{\text{cm}}^{-1}$, $\text{C-H}$ is $3000{\text{cm}}^{-1}$, $\text{C-C}$ is $1200{\text{cm}}^{-1}$ and $\text{C}=\text{O}$ is $1735{\text{cm}}^{-1}$.

(i)

Interpretation Introduction

To determine: The characteristic infrared absorptions of the functional groups in the given molecule.

Interpretation: The characteristic infrared absorptions of the functional groups in the given molecule are to be predicted.

Concept introduction: An IR spectrum is a graph for the energy absorbed by a molecule as a function of the frequency or wavelength of light. Alkanes, alkenes and alkynes have characteristic $\text{C}-\text{H}$ stretching frequencies. Isolated alkenes have value $1640-1680{\text{cm}}^{-1}$ and that of conjugated alkenes have $1620-1640{\text{cm}}^{-1}$ frequencies.

Answer to Problem 12.12SP

The characteristic infrared absorptions of the functional groups in the given molecule are,

Figure 17

Explanation of Solution

The structure of the given molecule is,

Figure 18

The possibilities of the IR stretching frequencies for the given molecule are shown as,

Figure 17

So, the stretching frequencies of $\text{C-H}$ is $3000{\text{cm}}^{-1}$, $\text{C-C}$ is $1200{\text{cm}}^{-1}$, $\text{C=O}$ is $1640{\text{cm}}^{-1}$ and $\text{N-H}$ is $3300{\text{cm}}^{-1}$.