Answer: Cl2 is acting as an oxidizing agent.
Explanation:
Hydrogen reacts with Chlorine to produce Hydrochloric Acid.
H2 + Cl2 ---> 2 HCl
Oxidation Reaction: Hydrogen's oxidation state in H2 is changing from 0 in H2 to +1 in HCl per atom. That means that it has lost one electron per atom and two electrons per molecule. Therefore, hydrogen is oxidized and has acted as a reducing agent.
H2 ---> 2 HCl + e-
Reduction Reaction: Chlorine's oxidation state in Cl2 is changing from 0 in Cl2 to -1 in HCl per atom. This means that it loses one electron per atom and two electrons per two atoms. Therefore, Chlorine is reduced and has acted as an oxidizing agent.