Oxidation is a process that involves

The correct option is A

The loss of electrons

The explanation of the correct option

Option (A) The loss of electrons

• The reaction in which there is the addition of an oxygen molecule (any electronegative element) or removal of a hydrogen molecule (any electropositive molecule) or loss of electrons is called oxidation.
• An example of an oxidation reaction is $\underset{\mathrm{Carbon}}{\mathrm{C}\left(\mathrm{s}\right)}+\underset{\mathrm{Oxygen}}{{\mathrm{O}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}$
• Here, oxygen is added to the carbon atom that is, oxidation takes place.
• Reduction is different from oxidation, the reaction in which there is the addition of a hydrogen molecule (any electropositive element) or removal of an Oxygen molecule (any electronegative molecule), or gaining electrons is called reduction.
• An example of a reduction reaction is $\underset{\mathrm{Zinc}\mathrm{oxide}}{\mathrm{ZnO}\left(\mathrm{s}\right)}+\underset{\mathrm{Carbon}\mathrm{monoxide}}{\mathrm{CO}\left(\mathrm{g}\right)}\to \underset{\mathrm{Zinc}}{\mathrm{Zn}\left(\mathrm{s}\right)}+\underset{\mathrm{Carbon}\mathrm{dioxide}}{{\mathrm{CO}}_2\left(\mathrm{g}\right)}$
• Here, oxygen is removed from the zinc atom that is, reduction takes place.
• Thus, oxidation is a process that involves the loss of electrons.
• Hence the correct option.

The explanation for incorrect option

Option (B) the gain of hydrogen

• Oxidation involves the gain of oxygen and the loss of hydrogen.
• Hence the incorrect option.

Option (C) the gain of electrons

• The gain of electrons occurs in the reduction process not in oxidation, while in the oxidation process atom loses one or more electrons.
• Hence the incorrect option.

Option (D) no change in electrons

• In the oxidation process atom losses one or more electrons.
• Hence the incorrect option.

Therefore, oxidation is a process that involves option (A) the loss of electrons.