Chapter 15, Problem 56PP

Interpretation Introduction

Interpretation: The molecular formula for the given compound limonene should be determined.

Concept Introduction:

Mass spectroscopy: It is a form of spectroscopic technique which is used for the elucidation of the molecular formula and molecular weight of the compound, depending upon the mass of the molecule.

Molecular formula: It represents the types of atoms with their total number present in a given molecule.

Molecular ion peak ${\text{(M)}}^{\text{+}·}$: It is defined as the heaviest peak in the IR spectrum of the molecule which represents the largest molecular ion in the given molecule with greater m/z value.

Base peak: It is the tallest peak in the spectrum.

The ${\text{(M+1)}}^{\text{+}·}$ peak: It denotes the peak that arises next to molecular ion peak in the mass spectrum. The peak arises due to the presence of the isotope of carbon $\left({}^{\text{13}}\text{C}\right).$

The ${\text{(M+1)}}^{\text{+}·}$ peak in mass spectroscopy is used to explain the number of carbon atoms present in a molecule depending on the abundance of ${\text{(M+1)}}^{\text{+}·}$ peak.

The Hydrogen Deficiency Index (HDI): It is used to measure the number of degrees of unsaturation (double and triple bonds) present in a given molecule. It is determined by using the formula $\begin{array}{l}\text{HDI}\text{=}\frac{\text{1}}{\text{2}}\text{[(2}\times \text{No}\text{. of Carbon atoms)+2+(No}\text{. of Nitrogen atoms)}\\ \text{-(No}\text{. of Hydrogen atoms)-(No}\text{. of halogens)]}\end{array}$

To determine: The molecular formula for the given compound.