Chapter 15.5, Problem 9P

(a)

Interpretation Introduction

Interpretation:

The change in the chemical shift value on changing the operating frequency of the spectrometer has to be determined.

Concept introduction:

The NMR spectrum of any compound is taken with reference to a standard compound called reference compound.  Generally, tetramethylsilane (TMS) is taken as the reference compound.  The methyl protons of TMS are equivalent and produces only one sharp peak at the rightmost end of the scale.

The distance between the TMS signal and the signals produced by the compound is called the chemical shift.  Chemical shift basically measures the shift in the signal position of the compound with respect to the reference signal.

Chemical shift in delta scale is given as,

$\text{chemical shift,}\delta \left(\text{ppm}\right)=\frac{\text{distance from the TMS signal}\left(\text{Hz}\right)}{\text{operating frequency of the spectrometer (MHz)}}$

(b)

Interpretation Introduction

Interpretation:

To determine the change in the chemical shift value on changing the operating frequency of the spectrometer.

Concept introduction:

The NMR spectrum of any compound is taken with reference to a standard compound called reference compound.  Generally, tetramethylsilane (TMS) is taken as the reference compound. The methyl protons of TMS are equivalent and produces only one sharp peak at the rightmost end of the scale.

The distance between the TMS signal and the signals produced by the compound is called the chemical shift.  Chemical shift basically measures the shift in the signal position of the compound with respect to the reference signal.

Chemical shift in delta scale is given as,

$\text{chemical shift,}\delta \left(\text{ppm}\right)=\frac{\text{distance from the TMS signal}\left(\text{Hz}\right)}{\text{operating frequency of the spectrometer (MHz)}}$