Which term refers to the molecule that donates electrons to another substance in a redox reaction?

• A. Oxidizing agent
• B. Catalyst
• C. Reducing agent
• D. Solvent

Answer: (C)

In redox reactions, electrons move from one molecule to another. The molecule that donates electrons is the reducing agent because it reduces the other substance by giving up electrons, and in the process it itself becomes oxidized. The partner that accepts those electrons is the oxidizing agent, which is reduced. The other options don’t describe electron donation: a catalyst speeds up reactions without being consumed, a solvent is just the medium, and the oxidizing agent is the species that accepts electrons rather than donates them. So the donor of electrons is the reducing agent.