Assessing statements on contact process reactions

Steps:

• Statement 1: Reaction 1 (2SO₂ + O₂ → 2SO₃) is reversible, as the contact process uses a catalyst to favor forward equilibrium despite the single arrow in the equation.
• Statement 2: ΔH = -198 kJ/mol for Reaction 1 is negative, confirming it is exothermic by thermodynamic definition.
• Statement 3: Reaction 2 shows SO₃ + H₂O → H₂SO₄, so sulfur dioxide (SO₂) does not react; it is SO₃, making this false.
• Correct choice: Only statements 1 and 2 hold, matching option A.

Why A is correct:

• A identifies statements 1 and 2 as true based on reaction reversibility in the process and exothermic ΔH < 0.

Why the others are wrong:

• B includes 3, but Reaction 2 uses SO₃, not SO₂.
• C excludes 1, but the oxidation is reversible under process conditions.
• D includes 3, which incorrectly names SO₂ as the reactant.

Final answer: A