Answer: Option C - Radical
Explanation:
A radical is a chemical specie carrying a lone electron. In the halogenation of alkanes: take Methane CH4 as the alkane, and Chlorine Cl as the halogen.
The step by step halogenation process is as follows:
CH4 + Cl2 --> CH3• + HCl + Cl•
CH3• + Cl2 --> CH3Cl + HCl
CH3Cl + Cl2 --> CH2Cl2 + HCl + Cl•
CH2Cl2 + Cl2 --> CHCl3 + HCl
CHCl3 + Cl2 --> CCl4 + HCl + Cl•
Chlorine molecule attack methane knocking off an hydrogen atom from it and forming a methyl radical (CH3•), that is subsequently attack by another chlorine molecule. This cycle repeats itself, until no hydrogen atom is available for substitution by the highly reactive chlorine radical.
Note: no cation or anion is formed in the halogenation process
