The Formation of Halogenoalkanes

Question 1

What is a free radical?

Answer 1

A chemical species with an unpaired electron- usually highly reactive.

Question 2

Describe the reaction mechanism for the free-radical substitution of methane.

Answer 2

INITIATION
-The Cl-Cl bond is broken
-Chlorine molecule absorbs the energy of a single quantum of UV light
-Homolytic, therefore an electronic goes to both atoms of chlorine. This is because they are the same type of atom
-Therefore free radicals are created, and have a dot to represent this.

PROPAGATION
-Chlorine free radical takes a hydrogen atom from methane to form hydrogen chloride. This leaves a methyl free radical.
-The methyl free radical is also very reactive and reacts with a Chlorine molecule.