Chemical agent and Reducing agent

Chemical agent noun - An agent that produces chemical reactions.

Reducing agent and chemical agent are semantically related. In some cases you can replace phrase "Reducing agent" with "Chemical agent", this phrases are similar.

Reducing agent noun - A substance capable of bringing about the reduction of another substance as it itself is oxidized; used in photography to lessen the density of a negative or print by oxidizing some of the loose silver.

Chemical agent and reducing agent are semantically related. You can use "Chemical agent" instead a noun phrase "Reducing agent".