How do alkanes participate in radical substitution reactions?

Alkanes participate in radical substitution reactions by reacting with halogens in the presence of ultraviolet light.

In more detail, alkanes are a type of hydrocarbon, which means they are composed of hydrogen and carbon atoms. They are known for their stability and low reactivity due to the non-polar nature of the C-H bonds. However, they can undergo a type of reaction known as radical substitution, particularly with halogens, when exposed to ultraviolet (UV) light.

The process of radical substitution involves three stages: initiation, propagation, and termination. In the initiation stage, the halogen molecules are broken down into radicals by the UV light. Radicals are highly reactive species with unpaired electrons.

In the propagation stage, the halogen radical collides with the alkane, breaking a C-H bond and forming a new C-X bond (X being the halogen). This process creates a new radical, which can then react with another halogen molecule, continuing the chain reaction.

Finally, in the termination stage, two radicals collide and combine to form a stable molecule, ending the chain reaction. The result of this process is a halogenoalkane, a molecule in which one or more of the hydrogen atoms in the alkane have been replaced by halogen atoms.

It's important to note that this reaction is not very selective. The radical can replace any hydrogen atom in the alkane, leading to a mixture of products. This lack of selectivity is one of the reasons why radical substitution is not commonly used in industrial organic synthesis. However, understanding this reaction is crucial for your chemistry studies as it illustrates the reactivity of alkanes and the concept of radical reactions.