Final answer:
In the reaction Mg + Fe²⁺ → Mg²⁺ + Fe, magnesium (Mg) is being oxidized and iron (Fe²⁺) is being reduced. Magnesium acts as the reducing agent, while iron is the oxidizing agent. This is determined by the changes in their oxidation states.
Step-by-step explanation:
The reaction given is Mg + Fe²⁺ → Mg²⁺ + Fe. In this redox reaction, magnesium (Mg) is oxidized, and iron (Fe²⁺) is reduced. To identify the oxidizing and reducing agents, we need to look at the changes in the oxidation states of the elements involved.
Magnesium starts with an oxidation state of 0 and ends up in a +2 state in Mg²⁺, thereby losing two electrons. Iron, on the other hand, starts with a +2 oxidation state and ends up with an oxidation state of 0, thus gaining two electrons. Since magnesium is losing electrons, it is being oxidized and acts as the reducing agent. Conversely, iron is gaining electrons, which means it is being reduced and is the oxidizing agent.
The species oxidized is Mg, going from Mg (0) to Mg²⁺ (+2), and the species reduced is Fe²⁺, going from Fe²⁺ (+2) to Fe (0).