Redox reactions pair oxidation and reduction

Steps:

• Recall that oxidation is electron loss and reduction is electron gain.
• Recognize that in redox reactions, electrons transfer from reducing agent to oxidizing agent, so both processes occur simultaneously.
• Evaluate each option against these definitions.
• Identify B as the only universally true statement.

Why B is correct:

• By definition, oxidation and reduction are complementary; electrons lost in oxidation are gained in reduction, making all such reactions redox processes (OIL RIG principle).

Why the others are wrong:

• A: Acidified manganate(VII) ions are purple and turn colourless (to Mn²⁺) when reduced.
• C: Oxidising agents gain electrons to become reduced themselves.
• D: Reduction is the gain of hydrogen (or electrons/oxygen loss), not loss.

Final answer: B