Chapter 2.2, Problem 2LTS

Interpretation Introduction

Interpretation:

The number of Carbon atoms and missing Hydrogen atoms are to be filled and identified.

Concept Introduction:

Molecular formula: Molecular formula is representation of number of atoms and number of each type in a molecule of a compound, but not their structural arrangement.

The Index of Hydrogen Deficiency (IHD) is otherwise called as units of unsaturation. IHD gives the count of number of Hydrogen molecules that are needed to add to a structure in order to form the corresponding saturated acyclic compound. Hence, the count of number of rings and multiple bonds seen in the structure are taken in consideration.

There are two ways of using IHD

1. 1) From a drawn structure: The number of rings and $\text{π}$ bonds present are counted. The $\text{π}$ bonds containing heteroatom (such as Oxygen, Nitrogen etc) are counted the same way as all Carbon bonds are counted.
2. 2) From the molecular formula: The IHD can also be given from molecular formula. The following generic molecular formula ${\text{C}}_{\text{c}}{\text{H}}_{\text{h}}{\text{N}}_{\text{n}}{\text{O}}_{\text{o}}{\text{X}}_{\text{x}}$ , then IHD equation can be derived ,

   $\text{IHD=0}\text{.5×[2c+2-h-x+n]}$