* Mechanism: Free-radical reactions involve the formation of highly reactive species with unpaired electrons. The reaction of ethene and chlorine proceeds through a two-step mechanism involving electrophilic attack.
* Step 1: The chlorine molecule (Cl2) is polarized by the double bond in ethene. This creates a partial positive charge on one chlorine atom and a partial negative charge on the other.
* Step 2: The electrophilic chlorine atom attacks the electron-rich double bond of ethene, forming a carbocation intermediate. The other chlorine atom then attacks the carbocation to form the final product, 1,2-dichloroethane.
* Conditions: Free-radical reactions typically require high temperatures or the presence of initiators to generate radicals. The reaction of ethene and chlorine can occur at room temperature or even lower temperatures, indicating that it doesn't involve free radicals.
* Products: Free-radical reactions often lead to a mixture of products due to the non-specific nature of radical attack. In contrast, the reaction of ethene and chlorine gives a single major product, 1,2-dichloroethane.
In summary: The reaction of ethene and chlorine is an electrophilic addition reaction because it involves the attack of an electrophilic species (chlorine) on an electron-rich alkene. The reaction proceeds via a specific mechanism and doesn't involve free radicals.
