Alkenes and alkynes that are saturated must have an index of hydrogen deficiency equal to zero as they have no carbon-carbon pi electron present in the system.

Question

Quizplus · Accepted Answer

Alkenes and alkynes, even if they are fully saturated, will still have an index of hydrogen deficiency (IHD) greater than zero due to the presence of double or triple bonds. The IHD is calculated as the number of missing hydrogens needed to achieve the maximum number of hydrogens possible for a given molecular formula, and is related to the number of unsaturated sites (pi bonds, rings, or multiple bonds) in the molecule.

Alkenes and Alkynes That Are Saturated Must Have an Index