What gas is commonly recognized as a reducing agent?

The gas that is commonly recognized as a reducing agent is carbon monoxide. Carbon monoxide has the ability to donate electrons in chemical reactions, which is a hallmark of a reducing agent. When carbon monoxide reacts with metal oxides, it helps to reduce the metal ions back to their elemental forms by removing oxygen. This process is essential in metallurgy, particularly in the extraction of metals from their ores.

In general, a reducing agent is a substance that loses electrons and causes another substance to be reduced. Carbon monoxide's ability to effectively donate electrons makes it a useful reducing agent in various chemical processes, particularly in the production of iron and other metals in blast furnaces.

In contrast, oxygen is typically an oxidizing agent, as it tends to gain electrons and facilitate oxidation reactions. Hydrogen can also act as a reducing agent under certain conditions, but it is less commonly recognized for this role compared to carbon monoxide in industrial processes. Nitrogen, on the other hand, is generally inert and does not participate in redox reactions as a reducing agent in the same way as carbon monoxide does.