Which statement correctly describes the oxidising agent?

• A. It loses electrons
• B. It gains electrons
• C. It is oxidised
• D. It is reduced

Answer: (B)

In redox chemistry, the oxidising agent is the substance that accepts electrons from another species, causing that other substance to be oxidised. Because it accepts electrons, it gains electrons and is reduced. So the statement that it gains electrons describes its role most directly. Saying it is reduced is also true, since gaining electrons is the same as being reduced, but the phrase “gains electrons” directly expresses the transfer happening in the reaction. The other descriptions describe the opposite behavior or the species being oxidised, which aren’t properties of the oxidising agent.