Oxides of elements and their redox properties

Steps:

• Identify oxides formed: Na → Na₂O, Mg → MgO, Al → Al₂O₃, S → SO₂.
• Classify oxide nature: Metal oxides (Na₂O, MgO, Al₂O₃) are basic/amphoteric and stable; SO₂ is acidic and reactive.
• Assess reducing agent role: Reducing agents get oxidized; check if oxide donates electrons.
• Select oxide that reduces others, like in reactions with oxidants.

Why D is correct:

• Sulfur forms SO₂, a reducing agent as it oxidizes to SO₃ (e.g., 2SO₂ + O₂ → 2SO₃), donating electrons per redox definition.

Why the others are wrong:

• A: Na₂O is a basic oxide that acts as an oxidizing agent, accepting electrons.
• B: MgO is a stable, refractory oxide with no reducing properties.
• C: Al₂O₃ is an amphoteric, inert oxide that does not donate electrons.

Final answer: D