Which of the following statements is associated with oxidation?

• A. An atom gains electrons during oxidation.
• B. Oxidation always involves the addition of hydrogen to a molecule.
• C. The oxidation number of an atom decreases during oxidation.
• D. An atom loses electrons during oxidation.

Answer: (D)

Verified step by step guidance

1. Recall the definition of oxidation in terms of electron transfer: Oxidation is the process where an atom, ion, or molecule loses electrons.
2. Understand that losing electrons means the oxidation number of the atom increases, not decreases, because electrons carry a negative charge.
3. Recognize that oxidation does not necessarily involve the addition of hydrogen; in fact, oxidation often involves the loss of hydrogen or gain of oxygen.
4. Compare the given statements with the definition: The correct statement about oxidation is that an atom loses electrons during oxidation.
5. Summarize that oxidation is characterized by electron loss, an increase in oxidation number, and is not defined by gaining electrons or adding hydrogen.