Question

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

$3\mathrm{Fe}+4{\mathrm{H}}_2\mathrm{O}\to {\mathrm{Fe}}_3{\mathrm{O}}_4+4{\mathrm{H}}_2$

Answer 1

1. Redox reactions

A reaction between two reactants in which one of the reactants is getting oxidized and the other is getting reduced is called a redox reaction. Redox reactions contain an oxidizing agent and a reducing agent.

Reducing agent: The element that loses and donates an electron is called a reducing agent.

Oxidizing agent: The element that gains and accepts an electron is called an oxidizing agent.

2. Identifying oxidizing and reducing agents

$$\begin{gathered} 3\mathrm{Fe}\left(\mathrm{s}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{Fe}}_3{\mathrm{O}}_4\left(\mathrm{s}\right)+4{\mathrm{H}}_2\left(\mathrm{g}\right) \\ \mathrm{Iron}\mathrm{Water}\mathrm{Iron}\mathrm{oxide}\mathrm{Hydrogen} \end{gathered}$$

The oxidation state of Iron changes from 0 in Iron to $\frac{8}{3}$ in Iron oxide $\left({\mathrm{Fe}}_3{\mathrm{O}}_4\right)$. Therefore, it is getting oxidized and is the reducing agent.

The oxidation state of Hydrogen changes from +1 in Water $\left({\mathrm{H}}_2\mathrm{O}\right)$ to 0 in Hydrogen $\left({\mathrm{H}}_2\right)$. Therefore, it is getting reduced and is the oxidizing agent.

Therefore, Iron is the reducing agent and Water is the oxidizing agent.