Colorado Esthetician Written Practice Exam 2026 - Free Esthetician Practice Questions and Study Guide

In a chemical reaction, oxidation involves the addition of oxygen or the loss of hydrogen. This process can be explained using the concept of the transfer of electrons. When a substance undergoes oxidation, it loses electrons, which are then gained by another substance undergoing reduction. This transfer of electrons is crucial in understanding redox reactions, where oxidation and reduction occur simultaneously. Therefore, in the context of oxidation, the correct answer is the addition of oxygen or the loss of hydrogen, as it reflects the fundamental principles of electron transfer in chemical reactions.