Alkenes exhibit a higher reactivity compared to alkanes primarily due to the presence of a carbon-carbon double bond.

Both alkenes and alkanes are classified as hydrocarbons, meaning they consist solely of hydrogen and carbon atoms. However, their reactivity differs significantly because of their structural characteristics. Alkanes are saturated hydrocarbons characterized by single bonds between carbon atoms, while alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond.

The carbon-carbon double bond in alkenes is central to their increased reactivity. This double bond is less stable than the single bonds found in alkanes, which makes alkenes more prone to engaging in chemical reactions. The double bond represents a region of high electron density, attracting electrophiles—species that are drawn to areas with high electron density. As a result, alkenes are particularly susceptible to addition reactions, in which a molecule is added to the double bond, causing it to break and form new single bonds.

In contrast, alkanes are relatively unreactive. Their single bonds are stable and do not easily dissociate to form new bonds. Alkanes are generally inert to most common laboratory reagents. They can undergo combustion reactions and substitution reactions under specific conditions, but these processes are less frequent and occur at a slower rate compared to the reactions of alkenes.

In conclusion, the presence of a carbon-carbon double bond in alkenes significantly enhances their reactivity relative to alkanes. This distinction in reactivity is a fundamental principle in organic chemistry and is essential for understanding the behavior of these hydrocarbons in various chemical contexts.