A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction (see electrochemistry) that reduces another species. In doing so, it becomes oxidized, and is therefore the electron donor in the redox. For example consider the following reaction: » [Fe(CN)6]4- + 1/2 Cl2 → [Fe(CN)6]3- + Cl The reducing agent in this reaction is ferrocyanide: it donates an electron, converting to ferricyanide, simultaneous with the reduction of chl… (More on Reductant)