Identify the reducing agent in the following reaction: $2{\mathrm{H}}_2+{\mathrm{O}}_2\to 2{\mathrm{H}}_2\mathrm{O}$

Reducing agent:

• A reducing agent is known as a chemical species which reduces the other substances by oxidizing itself in the chemical reaction.
• A reducing agent decreases the oxidation state of the reduced substance by making it to gain electrons, while the reducing agent increases its oxidation state by losing the electron.

The reducing agent in the given reaction:

• In the given reaction hydrogen reacts with oxygen to produce water.
• The balanced chemical reaction can be written as:

$\underset{\mathrm{Hydrogen}}{2\stackrel{0}{{\mathrm{H}}_2}}+\stackrel{0}{\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2}}\to \underset{\mathrm{Water}}{2\stackrel{+2}{{\mathrm{H}}_2}\stackrel{-2}{\mathrm{O}}}$

• In the above-given reaction, ${\mathrm{H}}_2$ is acting as a reducing agent, in which there is an increase in the oxidation state from $0\mathrm{to}+2$
• Hydrogen reduces the ${\mathrm{O}}_2$ to water by decreasing its oxidation state from $0\mathrm{to}-2.$.

Hence, ${\mathrm{H}}_2$ is a reducing agent in the given reaction.