Chapter 15, Problem 15.19YT

Interpretation Introduction

Interpretation:

The alkane $\text{C-H}$ stretching absorption bands in Figure 15-23a and 15-23b are to be identified. In Figure 15-23c, where alkane $\text{C-H}$ stretching bands would normally appear is to be indicated.

Concept introduction:

Alkane $\text{C-H}$ stretches, which appear between $\text{28}00$ and ${\text{3000 cm}}^{\text{-1}}$, are so commonplace in organic molecules that they are generally not useful in structure elucidation. The alkane $\text{C-H}$ stretching band is perhaps most useful when it is low in intensity or absent altogether. This is because the relative intensity of the alkane $\text{C-H}$ band decreases as the relative number of alkane $\text{C-H}$ bonds in the molecule decreases.