The reducing agent in a redox reaction donates electrons to the oxidizing agent, causing the oxidizing agent to be reduced. In other words, the reducing agent is oxidized in the reaction.

Here's a more detailed explanation:

* In a redox reaction, one species undergoes oxidation (loss of electrons) while another species undergoes reduction (gain of electrons).

* The reducing agent is the species that undergoes oxidation. It donates electrons to the oxidizing agent, causing the oxidizing agent to be reduced.

* The reducing agent is typically a metal or a compound that contains a metal in a low oxidation state. Examples of reducing agents include sodium metal (Na), iron(II) sulfate (FeSO4), and hydrogen gas (H2).

* When the reducing agent donates electrons to the oxidizing agent, its own oxidation state increases. For example, when iron(II) sulfate is oxidized, it is converted to iron(III) sulfate.

Overall, the reducing agent in a redox reaction is responsible for transferring electrons to the oxidizing agent, causing the oxidizing agent to be reduced.