Verifying industrial uses of sulfur compounds

Steps:

• Recall the Contact process: sulfur burns to SO2, then SO2 oxidizes to SO3 using O2 and catalyst.
• Check food preservation: SO2 acts as antioxidant and antimicrobial agent.
• Evaluate SO2 in paper production: used in sulfite process to break down lignin, not primarily for bacteria.
• Assess H2SO4 properties: strong acid for dehydration and catalysis, not bleaching.

Why A is correct:

• Sulfur dioxide (SO2) preserves food by inhibiting microbial growth and oxidation, as per food chemistry standards.

Why the others are wrong:

• B: In Contact process, SO2 (not sulfur) reacts with O2 to form SO3: 2SO2 + O2 → 2SO3.
• C: SO2 aids lignin removal in wood pulp for papermaking, but chlorine compounds kill bacteria.
• D: Sulfuric acid dehydrates and corrodes; bleaches like ClO2 oxidize color without acidity.

Final answer: A