Chapter 12.12, Problem 12.6P

Interpretation Introduction

Interpretation: All the significant stretching frequencies above $1580{\text{cm}}^{-1}$ for each given spectrums are to be interpreted.

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.

The energy required to stretch a bond is more as compared to that of bending of a bond. $\text{C}-\text{H},\text{N}-\text{H}$ and $\text{O}-\text{H}$ bonds have much higher stretching frequencies as compared to those of corresponding bonds to heavier atoms.

To determine: All the significant stretching frequencies above $1580{\text{cm}}^{-1}$ for each given spectrums.