How do reducing agents work in redox reactions?

Reducing agents work in redox reactions by donating electrons to other substances, thereby reducing them.

In a redox (reduction-oxidation) reaction, there are two key players: the reducing agent and the oxidising agent. The reducing agent, as the name suggests, is responsible for the reduction part of the reaction. Reduction, in chemical terms, refers to the gain of electrons. So, a reducing agent works by giving away its own electrons to another substance, thus reducing that substance.

The reducing agent itself undergoes oxidation in the process. Oxidation is the loss of electrons. So, when a reducing agent donates its electrons to another substance, it loses those electrons and is therefore oxidised. This is why redox reactions are always paired: when one substance is reduced, another is oxidised.

For example, consider the reaction between zinc and hydrochloric acid. In this reaction, zinc (Zn) acts as the reducing agent. It donates two electrons to two hydrogen ions (H+) from the hydrochloric acid. The hydrogen ions gain these electrons (are reduced) and form hydrogen gas (H2), while the zinc loses two electrons (is oxidised) and forms zinc ions (Zn2+).

The ability of a substance to act as a reducing agent depends on its willingness to lose electrons. This is often related to the substance's position in the reactivity series. Metals, for instance, are often good reducing agents because they readily lose electrons. Conversely, non-metals are often good oxidising agents because they readily gain electrons.

In summary, reducing agents play a crucial role in redox reactions. They donate their electrons to other substances, enabling these substances to be reduced. In the process, the reducing agents themselves are oxidised. Understanding this electron transfer is key to understanding redox reactions.