Chapter 13, Problem 13.25P

(a)

Interpretation Introduction

Interpretation:

The coupling constant for ethylene and acetylene molecules have to be calculated.

Concept introduction:

The single ${}^{\text{1}}\text{H NMR}$ signal is split into multiple peaks called the multiplicity of the signal.  Splitting of signals is done according to the $\left(N+\text{1}\right)$) rule.  N is the number of adjacent nonequivalent protons.  According to the $\left(N+\text{1}\right)$ rule, for a proton-coupled with N adjacent nonequivalent protons, the signal split into $\left(N+\text{1}\right)$ peak.  The splitting is mutual.  Splitting occurs only due to nonequivalent protons that are the protons present in the different chemical environment.

The distance between any two adjacent peaks is called coupling constant in hertz represented as $J$.  The value of coupling constant for two protons coupling with each other is same.  Thus the coupling constant gives vital information about the adjacent groups or protons because protons on adjacent carbons have a similar coupling constant.

(b)

Interpretation Introduction

Interpretation:

The hybridization of cyclopropane molecule coupling has to be detremined using the given data of coupling constant.

Concept introduction:

The single ${}^{\text{1}}\text{H NMR}$ signal is split into multiple peaks called the multiplicity of the signal.  Splitting of signals is done according to the $\left(N+\text{1}\right)$) rule.  N is the number of adjacent nonequivalent protons.  According to the $\left(N+\text{1}\right)$ rule, for a proton-coupled with N adjacent nonequivalent protons, the signal split into $\left(N+\text{1}\right)$ peak.  The splitting is mutual.  Splitting occurs only due to nonequivalent protons that are the protons present in the different chemical environment.

The distance between any two adjacent peaks is called coupling constant in hertz represented as $J$.  The value of coupling constant for two protons coupling with each other is same.  Thus the coupling constant gives vital information about the adjacent groups or protons because protons on adjacent carbons have a similar coupling constant.