In a redox reaction, what happens to a substance when it becomes oxidized, and what happens when it is reduced?

• A. It loses electrons when oxidized and gains electrons when reduced.
• B. It gains protons when oxidized and loses protons when reduced.
• C. It gains electrons when oxidized and loses electrons when reduced.
• D. It loses protons when oxidized and gains protons when reduced.

Answer: (A)

Verified step by step guidance

1. Understand the concept of a redox reaction: Redox reactions involve the transfer of electrons between two substances. The term 'redox' is a combination of 'reduction' and 'oxidation'.
2. Define oxidation and reduction: Oxidation is the process where a substance loses electrons, while reduction is the process where a substance gains electrons.
3. Identify the role of electrons: In a redox reaction, the substance that loses electrons is said to be oxidized, and the substance that gains electrons is said to be reduced.
4. Clarify the misconception about protons: Redox reactions primarily involve the transfer of electrons, not protons. Therefore, changes in protons are not relevant to the definition of oxidation and reduction.
5. Summarize the correct understanding: In a redox reaction, a substance is oxidized when it loses electrons and reduced when it gains electrons. This is the fundamental principle of redox chemistry.