Which term refers to the reactant in a redox reaction that donates electrons and becomes oxidized?

• A. Oxidizing Agent
• B. Reducing Agent
• C. Anode
• D. Cathode

Answer: (B)

In a redox reaction, oxidation is the loss of electrons and reduction is the gain of electrons. The reactant that donates electrons is the reducing agent because by giving electrons it gets oxidized itself while causing the other species to reduce. The name directly reflects its role: it reduces the other substance by supplying electrons, and in doing so it is oxidized.

For example, in a classic Zn and Cu2+ system, zinc metal loses electrons to become Zn2+. It donates electrons to the copper ions, so zinc acts as the reducing agent, while Cu2+ is reduced to copper and acts as the oxidizing agent. The terms anode and cathode describe where oxidation and reduction occur in a cell, but the term that identifies the reactant that donates electrons is reducing agent.