GKFix MCQ Question

What is the chemical equation for the key reaction in the Contact Process?

• A. SO2(g) + O2(g) → SO3(g)
• B. 2SO2(g) + O2(g) → 2SO3(g)
• C. SO2(g) + H2O(l) → H2SO3(aq)
• D. 2SO3(g) + O2(g) → 2SO4(g)