Charcoal is used as a fuel and as a reducing agent in metallurgical processes.
It is found that if the inoculation be made deep down in a solid medium, growth of an anaerobic organism will take place, especially if the medium contains some reducing agent such as glucose.
Dewar and Jones suggest that in the latter reaction it is the metallic nickel which is probably the reducing agent effecting the change, since it is only dissolved in any quantity when the anthracene hydrocarbon is produced.
Potassium ferrous oxalate, FeK2(C204)2 H20, is a strong reducing agent and is used as a photographic developer.
In aqueous solution the free acid acts as an oxidizing agent, bleaching indigo and liberating iodine from potassium iodide, or it may act as a reducing agent since it readily tends to pass into nitric acid: consequently it discharges the colour of acid solutions of permanganates and chromates.