Oxidation in chemical reactions is the _____________

Correct option is D

Ans (d)
Sol. Loss of nitrogen: Oxidation does not specifically involve the loss of nitrogen. Nitrogen can be involved in other chemical reactions, but it is not a defining characteristic of oxidation.
Loss of oxygen: This is the opposite of oxidation. When a substance loses oxygen, it undergoes reduction, not oxidation.
Gain of hydrogen: This is typically associated with reduction, not oxidation. In reduction, a substance gains hydrogen or electrons.
Gain of oxygen : Oxidation is defined as the process in which a substance gains oxygen, loses electrons, or increases its oxidation state. This is a key concept in redox (reduction-oxidation) reactions.