What is a reduction reaction? Give an example

Reduction reaction:

• Reduction is a half-reaction in which a chemical species reduces its oxidation number by gaining electrons.
• Reduction is the gain of electrons or a decrease in the oxidation state of a chemical or atoms within it.

Example of Reduction:

• The reaction given below would be the example of reduction, in this reaction ${\mathrm{H}}^{+}$ ions with an oxidation number of +1 are reduced to ${\mathrm{H}}_2$ ions having an oxidation number of zero.
• The chemical reaction can be depicted as:

$\mathrm{Zn}\left(\mathrm{s}\right)+2{\mathrm{H}}^{+}\left(\mathrm{aq}\right)\stackrel{}{\to }{\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$