Chemical agent and Reductant

Chemical agent noun - An agent that produces chemical reactions.

Reductant and chemical agent are semantically related. In some cases you can replace term "Reductant" with "Chemical agent", this terms are similar.

Reductant 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 reductant are semantically related. You can use "Chemical agent" instead a noun "Reductant".