Which statement best explains the relationship between oxidation and reduction in a redox reaction?

• A. Reduction only occurs if oxygen is present in the reaction.
• B. Oxidation and reduction always occur together; when one molecule is oxidized, another is reduced.
• C. Oxidation can occur without reduction in some chemical reactions.
• D. Oxidation and reduction are independent processes that do not affect each other.

Answer: (B)

Verified step by step guidance

1. Understand that redox reactions involve the transfer of electrons between species.
2. Recognize that oxidation is the loss of electrons, while reduction is the gain of electrons.
3. Know that because electrons cannot simply disappear, when one species loses electrons (oxidized), another must gain those electrons (reduced).
4. Therefore, oxidation and reduction always occur simultaneously in a redox reaction; one cannot happen without the other.
5. Note that the presence of oxygen is not required for reduction, and oxidation cannot occur without a corresponding reduction.