Given the molecular formula, calculate the index of hydrogen deficiency.
(b) C₄H₉ON

The Index of Hydrogen Deficiency (IHD) is a measure of the degree of unsaturation in a molecular formula. It indicates the number of rings and/or multiple bonds present in a compound. Each double bond or ring contributes one to the IHD, while each triple bond contributes two. The formula for calculating IHD is IHD = (2C + 2 + N - H - X) / 2, where C is the number of carbons, N is the number of nitrogens, H is the number of hydrogens, and X is the number of halogens.

A molecular formula provides the number and types of atoms in a molecule, but does not indicate the structure. In the case of C₄H₉ON, the formula indicates four carbon atoms, nine hydrogen atoms, one oxygen atom, and one nitrogen atom. Understanding how to interpret this formula is crucial for calculating the IHD, as it allows for the identification of the elements involved and their contributions to the overall saturation of the molecule.

Unsaturation refers to the presence of double or triple bonds in organic compounds, which affects their reactivity and physical properties. Compounds with higher unsaturation typically have lower hydrogen counts relative to their carbon counts. Recognizing the implications of unsaturation is essential for predicting the behavior of organic molecules, including their stability and potential reactions, which is directly related to the calculation of the IHD.