Question

Identify the reducing agent and oxidizing agent in the following reactions:

$2\mathrm{Mg}+{\mathrm{O}}_2\to 2\mathrm{MgO}$

Answer 1

1. Redox reactions

Reactions that involve the loss of electrons are called oxidation and it causes an increase in the oxidation state of the species. A decrease in the oxidation state of the species is caused by the addition of electrons and is caused by the addition of electrons. These reactions are called reduction reactions. In a redox reaction, the species that donates the electron is called a reducing agent, and the species that accepts the electron is called an oxidizing agent.

Therefore, the oxidizing agent and the reducing agent in a redox reaction can be identified by the difference in the oxidation state of the reactants.

2. Identifying oxidizing and reducing agents

$$\begin{gathered} 2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right) \\ \mathrm{Magnesium}\mathrm{Oxygen}\mathrm{Magnesium}\mathrm{oxide} \end{gathered}$$

The oxidation state of Magnesium $\left(\mathrm{Mg}\right)$ changes from 0 in Magnesium to +2 in Magnesium oxide $\left(\mathrm{MgO}\right)$. Therefore, it undergoes oxidation and is the reducing agent.

The oxidation state of Oxygen $\left(\mathrm{O}\right)$ decreases from 0 in Oxygen $\left({\mathrm{O}}_2\right)$ to -2 in Magnesium oxide. Therefore, it undergoes reduction and is the oxidizing agent.

Therefore, Magnesium is the reducing agent and Oxygen is the oxidizing agent.