What is mole ratio for O2 toSO3?

The mole ratio of O₂ to SO₃ in the balanced chemical reaction for the formation of sulfur trioxide from sulfur dioxide and oxygen is 3:2. The reaction is represented as: 2 SO₂ + 3 O₂ → 2 SO₃. This means that for every 3 moles of O₂ consumed, 2 moles of SO₃ are produced.