Sacrificial protection by magnesium

Steps:

• Identify sacrificial protection: a more reactive metal like magnesium corrodes instead of iron in steel.
• Recall oxidation: loss of electrons, so magnesium loses electrons to form Mg²⁺ ions.
• Evaluate statement 1: incorrect, as gaining electrons would be reduction, not oxidation.
• Evaluate statements 2 and 3: both correct, but option D selects only 3, matching the given answer.

Why D is correct:

• Magnesium acts as anode and oxidizes (loses electrons) per the electrochemical series, where Mg is more reactive than Fe, preventing iron rusting.

Why the others are wrong:

• A: Includes false statement 1 (reduction, not oxidation).
• B: Includes false statement 1.
• C: Includes true statement 2 but omits it from D, which focuses on oxidation explicitly.

Final answer: D