Chapter 7, Problem 46P

Interpretation Introduction

Interpretation:

The number of double bonds and number of rings in a molecule of caryophyllene is to be determined.

Concept Introduction:

▸ The reaction in which hydrogen is added to a compound in the presence of a catalyst is known as hydrogenation.

▸ The number of moles of hydrogen absorbed will be equal to the number of double bonds.

▸ The change in number of pairs of hydrogen atoms of a given compound and the acyclic compound which has the number of carbon atoms same as the number of carbon atoms in the given compound, is known as the Index of hydrogen deficiency.

▸ The Index of hydrogen deficiency can be denoted by IHD.

▸ The Index of hydrogen deficiency can be calculated by using the formula given below:

$\begin{array}{c}\text{IHD}=\text{rings}+\pi \text{bonds}\\ =\text{C}-\frac{\text{H}}{2}-\frac{\text{X}}{2}+\frac{\text{N}}{2}+1\end{array}$

Here, C represents the number of carbon atoms, H represents the number of hydrogen atoms, N represents the number of nitrogen atoms and X represents the number of halogen atoms.

▸ The compound caryophyllene has molecular formula ${\text{C}}_{\text{15}}{\text{H}}_{24}$, on hydrogenation it converts into ${\text{C}}_{\text{15}}{\text{H}}_{28}$.