Colorado Esthetician Written Practice Exam

What does reduction involve in a chemical reaction?

1. Gain of oxygen or loss of hydrogen

2. Addition of hydrogen or loss of oxygen

3. Loss of electrons

4. Addition of neutrons

The correct answer is: Addition of hydrogen or loss of oxygen

Reduction in a chemical reaction involves the addition of hydrogen or the loss of oxygen. This process occurs when a molecule gains electrons or decreases its oxidation state. Redox reactions involve both reduction and oxidation, where reduction is characterized by the gaining of electrons or the addition of hydrogen atoms. In contrast, the other options are not accurate descriptions of reduction.