Final answer:
The reactivity of compounds with multiple bonds is increased due to higher electron density and exposure of π-electrons, making them more susceptible to attack by electrophilic reagents.
Step-by-step explanation:
The presence of a multiple bond increases the reactivity of a compound for several reasons. First, multiple bonds, such as double or triple bonds, have a higher electron density than single bonds. This increased electron density can cause the compound to be more reactive towards electrophilic agents that are attracted to regions of high electron density. Moreover, the electron density in π-bonds is more exposed and less tightly held than in σ-bonds, allowing for easier interaction with electrophilic reagents, resulting in a reaction where a new σ-bond is formed.
Additionally, compounds with multiple bonds may have substituents that donate electrons, further increasing electron density and reactivity. For instance, the presence of electron-donating groups on an aromatic ring makes it more reactive towards electrophiles by increasing the overall electron density. Furthermore, the phenomenon of resonance stabilization, where π- or nonbonding electrons are delocalized over several nuclei, can contribute to the stability of compounds, potentially making them reactive in certain chemical environments.
In summary, the structural and electronic attributes of multiple bonds make compounds containing them more likely to participate in chemical reactions, especially those involving electrophilic species that seek out areas of high electron density.